diff --git a/code/3DS/3DSLoader.cpp b/code/3DS/3DSLoader.cpp
index 96b80c962..3c659d0b0 100644
--- a/code/3DS/3DSLoader.cpp
+++ b/code/3DS/3DSLoader.cpp
@@ -50,9 +50,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef ASSIMP_BUILD_NO_3DS_IMPORTER
 
-// internal headers
 #include "3DSLoader.h"
-#include <assimp/Macros.h>
 #include <assimp/IOSystem.hpp>
 #include <assimp/scene.h>
 #include <assimp/DefaultLogger.hpp>
diff --git a/code/CMakeLists.txt b/code/CMakeLists.txt
index 55538d965..eec805b54 100644
--- a/code/CMakeLists.txt
+++ b/code/CMakeLists.txt
@@ -137,7 +137,6 @@ SET( PUBLIC_HEADERS
   ${HEADER_PATH}/irrXMLWrapper.h
   ${HEADER_PATH}/BlobIOSystem.h
   ${HEADER_PATH}/MathFunctions.h
-  ${HEADER_PATH}/Macros.h
   ${HEADER_PATH}/Exceptional.h
   ${HEADER_PATH}/ByteSwapper.h
 )
@@ -1059,6 +1058,8 @@ MESSAGE(STATUS "Disabled importer formats:${ASSIMP_IMPORTERS_DISABLED}")
 MESSAGE(STATUS "Enabled exporter formats:${ASSIMP_EXPORTERS_ENABLED}")
 MESSAGE(STATUS "Disabled exporter formats:${ASSIMP_EXPORTERS_DISABLED}")
 
+SOURCE_GROUP( include\\assimp    FILES ${PUBLIC_HEADERS} )
+
 SET( assimp_src
   # Assimp Files
   ${Core_SRCS}
diff --git a/code/Irr/IRRMeshLoader.cpp b/code/Irr/IRRMeshLoader.cpp
index f3aed5943..057218464 100644
--- a/code/Irr/IRRMeshLoader.cpp
+++ b/code/Irr/IRRMeshLoader.cpp
@@ -57,7 +57,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/material.h>
 #include <assimp/scene.h>
 #include <assimp/importerdesc.h>
-#include <assimp/Macros.h>
 
 using namespace Assimp;
 using namespace irr;
diff --git a/code/MDL/MDLLoader.cpp b/code/MDL/MDLLoader.cpp
index 9c9ce2330..d71057d55 100644
--- a/code/MDL/MDLLoader.cpp
+++ b/code/MDL/MDLLoader.cpp
@@ -52,7 +52,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "MDL/MDLDefaultColorMap.h"
 #include "MD2/MD2FileData.h"
 
-#include <assimp/Macros.h>
 #include <assimp/qnan.h>
 #include <assimp/StringUtils.h>
 #include <assimp/Importer.hpp>
diff --git a/code/Material/MaterialSystem.cpp b/code/Material/MaterialSystem.cpp
index ecdf9942c..0be6e9f7b 100644
--- a/code/Material/MaterialSystem.cpp
+++ b/code/Material/MaterialSystem.cpp
@@ -51,7 +51,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/types.h>
 #include <assimp/material.h>
 #include <assimp/DefaultLogger.hpp>
-#include <assimp/Macros.h>
 
 using namespace Assimp;
 
diff --git a/code/Ply/PlyLoader.cpp b/code/Ply/PlyLoader.cpp
index 3924305cb..ca1ec22f8 100644
--- a/code/Ply/PlyLoader.cpp
+++ b/code/Ply/PlyLoader.cpp
@@ -49,7 +49,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // internal headers
 #include "PlyLoader.h"
 #include <assimp/IOStreamBuffer.h>
-#include <assimp/Macros.h>
 #include <memory>
 #include <assimp/IOSystem.hpp>
 #include <assimp/scene.h>
diff --git a/code/PostProcessing/FindInvalidDataProcess.cpp b/code/PostProcessing/FindInvalidDataProcess.cpp
index 433f04244..016884c6e 100644
--- a/code/PostProcessing/FindInvalidDataProcess.cpp
+++ b/code/PostProcessing/FindInvalidDataProcess.cpp
@@ -52,7 +52,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "FindInvalidDataProcess.h"
 #include "ProcessHelper.h"
 
-#include <assimp/Macros.h>
 #include <assimp/Exceptional.h>
 #include <assimp/qnan.h>
 
diff --git a/include/assimp/BaseImporter.h b/include/assimp/BaseImporter.h
index 55f7fe375..bd0451be3 100644
--- a/include/assimp/BaseImporter.h
+++ b/include/assimp/BaseImporter.h
@@ -41,9 +41,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /** @file Definition of the base class for all importer worker classes. */
+#pragma once
 #ifndef INCLUDED_AI_BASEIMPORTER_H
 #define INCLUDED_AI_BASEIMPORTER_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include "Exceptional.h"
 
 #include <vector>
diff --git a/include/assimp/Bitmap.h b/include/assimp/Bitmap.h
index e6b5fb132..4c3f5a437 100644
--- a/include/assimp/Bitmap.h
+++ b/include/assimp/Bitmap.h
@@ -46,10 +46,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Used for file formats which embed their textures into the model file.
  */
-
+#pragma once
 #ifndef AI_BITMAP_H_INC
 #define AI_BITMAP_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include "defs.h"
 #include <stdint.h>
 #include <cstddef>
diff --git a/include/assimp/ByteSwapper.h b/include/assimp/ByteSwapper.h
index 20a2463fb..3f14c471a 100644
--- a/include/assimp/ByteSwapper.h
+++ b/include/assimp/ByteSwapper.h
@@ -42,9 +42,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /** @file Helper class tp perform various byte oder swappings
    (e.g. little to big endian) */
+#pragma once
 #ifndef AI_BYTESWAPPER_H_INC
 #define AI_BYTESWAPPER_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/ai_assert.h>
 #include <assimp/types.h>
 #include <stdint.h>
diff --git a/include/assimp/CreateAnimMesh.h b/include/assimp/CreateAnimMesh.h
index a60173588..1266d1de1 100644
--- a/include/assimp/CreateAnimMesh.h
+++ b/include/assimp/CreateAnimMesh.h
@@ -43,16 +43,26 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file CreateAnimMesh.h
  *  Create AnimMesh from Mesh
  */
+#pragma once
 #ifndef INCLUDED_AI_CREATE_ANIM_MESH_H
 #define INCLUDED_AI_CREATE_ANIM_MESH_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/mesh.h>
 
-namespace Assimp    {
+namespace Assimp {
 
-/** Create aiAnimMesh from aiMesh. */
+/**
+ *  Create aiAnimMesh from aiMesh.
+ *  @param  mesh    The input mesh to create an animated mesh from.
+ *  @return The new created animated mesh.
+ */
 ASSIMP_API aiAnimMesh *aiCreateAnimMesh(const aiMesh *mesh);
 
 } // end of namespace Assimp
+
 #endif // INCLUDED_AI_CREATE_ANIM_MESH_H
 
diff --git a/include/assimp/DefaultIOStream.h b/include/assimp/DefaultIOStream.h
index 994d728ff..c6d382c1b 100644
--- a/include/assimp/DefaultIOStream.h
+++ b/include/assimp/DefaultIOStream.h
@@ -41,15 +41,20 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /** @file Default file I/O using fXXX()-family of functions */
+#pragma once
 #ifndef AI_DEFAULTIOSTREAM_H_INC
 #define AI_DEFAULTIOSTREAM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <stdio.h>
 #include <assimp/IOStream.hpp>
 #include <assimp/importerdesc.h>
 #include <assimp/Defines.h>
 
-namespace Assimp    {
+namespace Assimp {
 
 // ----------------------------------------------------------------------------------
 //! @class  DefaultIOStream
@@ -57,8 +62,7 @@ namespace Assimp    {
 //! @note   An instance of this class can exist without a valid file handle
 //!         attached to it. All calls fail, but the instance can nevertheless be
 //!         used with no restrictions.
-class ASSIMP_API DefaultIOStream : public IOStream
-{
+class ASSIMP_API DefaultIOStream : public IOStream {
     friend class DefaultIOSystem;
 #if __ANDROID__
 # if __ANDROID_API__ > 9
@@ -82,7 +86,6 @@ public:
         size_t pSize,
         size_t pCount);
 
-
     // -------------------------------------------------------------------
     /// Write to stream
     size_t Write(const void* pvBuffer,
@@ -107,16 +110,13 @@ public:
     void Flush();
 
 private:
-    //  File data-structure, using clib
     FILE* mFile;
-    //  Filename
     std::string mFilename;
-    // Cached file size
     mutable size_t mCachedSize;
 };
 
 // ----------------------------------------------------------------------------------
-inline
+AI_FORCE_INLINE
 DefaultIOStream::DefaultIOStream() AI_NO_EXCEPT
 : mFile(nullptr)
 , mFilename("")
@@ -125,7 +125,7 @@ DefaultIOStream::DefaultIOStream() AI_NO_EXCEPT
 }
 
 // ----------------------------------------------------------------------------------
-inline
+AI_FORCE_INLINE
 DefaultIOStream::DefaultIOStream (FILE* pFile, const std::string &strFilename)
 : mFile(pFile)
 , mFilename(strFilename)
@@ -137,4 +137,3 @@ DefaultIOStream::DefaultIOStream (FILE* pFile, const std::string &strFilename)
 } // ns assimp
 
 #endif //!!AI_DEFAULTIOSTREAM_H_INC
-
diff --git a/include/assimp/DefaultIOSystem.h b/include/assimp/DefaultIOSystem.h
index 2dd5c801b..46f6d447c 100644
--- a/include/assimp/DefaultIOSystem.h
+++ b/include/assimp/DefaultIOSystem.h
@@ -41,9 +41,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /** @file Default implementation of IOSystem using the standard C file functions */
+#pragma once
 #ifndef AI_DEFAULTIOSYSTEM_H_INC
 #define AI_DEFAULTIOSYSTEM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/IOSystem.hpp>
 
 namespace Assimp    {
diff --git a/include/assimp/Defines.h b/include/assimp/Defines.h
index 15e1d83c2..be3e2fafd 100644
--- a/include/assimp/Defines.h
+++ b/include/assimp/Defines.h
@@ -38,6 +38,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------
 */
 
+#pragma once
+#ifndef AI_DEFINES_H_INC
+#define AI_DEFINES_H_INC
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 // We need those constants, workaround for any platforms where nobody defined them yet
 #if (!defined SIZE_MAX)
 #   define SIZE_MAX (~((size_t)0))
@@ -47,3 +55,4 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #   define UINT_MAX (~((unsigned int)0))
 #endif
 
+#endif // AI_DEINES_H_INC
diff --git a/include/assimp/Exceptional.h b/include/assimp/Exceptional.h
index 5109b8f07..6bb6ce1e3 100644
--- a/include/assimp/Exceptional.h
+++ b/include/assimp/Exceptional.h
@@ -38,11 +38,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------
 */
 
-#ifndef INCLUDED_EXCEPTIONAL_H
-#define INCLUDED_EXCEPTIONAL_H
+#pragma once
+#ifndef AI_INCLUDED_EXCEPTIONAL_H
+#define AI_INCLUDED_EXCEPTIONAL_H
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
 
 #include <stdexcept>
 #include <assimp/DefaultIOStream.h>
+
 using std::runtime_error;
 
 #ifdef _MSC_VER
@@ -53,17 +59,14 @@ using std::runtime_error;
 /** FOR IMPORTER PLUGINS ONLY: Simple exception class to be thrown if an
  *  unrecoverable error occurs while importing. Loading APIs return
  *  NULL instead of a valid aiScene then.  */
-class DeadlyImportError
-    : public runtime_error
-{
+class DeadlyImportError : public runtime_error {
 public:
     /** Constructor with arguments */
     explicit DeadlyImportError( const std::string& errorText)
-        : runtime_error(errorText)
-    {
+    : runtime_error(errorText) {
+        // empty
     }
 
-private:
 };
 
 typedef DeadlyImportError DeadlyExportError;
@@ -84,7 +87,7 @@ struct ExceptionSwallower   {
 template <typename T>
 struct ExceptionSwallower<T*>   {
     T* operator ()() const {
-        return NULL;
+        return nullptr;
     }
 };
 
@@ -122,4 +125,4 @@ struct ExceptionSwallower<void> {
     }\
 }
 
-#endif // INCLUDED_EXCEPTIONAL_H
+#endif // AI_INCLUDED_EXCEPTIONAL_H
diff --git a/include/assimp/Exporter.hpp b/include/assimp/Exporter.hpp
index ea0303e80..2612e1f9d 100644
--- a/include/assimp/Exporter.hpp
+++ b/include/assimp/Exporter.hpp
@@ -48,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_EXPORT_HPP_INC
 #define AI_EXPORT_HPP_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifndef ASSIMP_BUILD_NO_EXPORT
 
 #include "cexport.h"
diff --git a/include/assimp/GenericProperty.h b/include/assimp/GenericProperty.h
index 183ecd519..7796d595b 100644
--- a/include/assimp/GenericProperty.h
+++ b/include/assimp/GenericProperty.h
@@ -40,12 +40,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------
 */
 
+#pragma once
 #ifndef AI_GENERIC_PROPERTY_H_INCLUDED
 #define AI_GENERIC_PROPERTY_H_INCLUDED
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/Importer.hpp>
 #include <assimp/ai_assert.h>
-#include "Hash.h"
+#include <assimp/Hash.h>
 
 #include <map>
 
diff --git a/include/assimp/Hash.h b/include/assimp/Hash.h
index 30657be19..905644078 100644
--- a/include/assimp/Hash.h
+++ b/include/assimp/Hash.h
@@ -39,10 +39,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----------------------------------------------------------------------
 */
-
+#pragma once
 #ifndef AI_HASH_H_INCLUDED
 #define AI_HASH_H_INCLUDED
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <stdint.h>
 #include <string.h>
 
diff --git a/include/assimp/IOStream.hpp b/include/assimp/IOStream.hpp
index 0623d0f70..39932cd94 100644
--- a/include/assimp/IOStream.hpp
+++ b/include/assimp/IOStream.hpp
@@ -48,14 +48,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_IOSTREAM_H_INC
 #define AI_IOSTREAM_H_INC
 
-#include "types.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/types.h>
 
 #ifndef __cplusplus
 #   error This header requires C++ to be used. aiFileIO.h is the \
     corresponding C interface.
 #endif
 
-namespace Assimp    {
+namespace Assimp {
 
 // ----------------------------------------------------------------------------------
 /** @brief CPP-API: Class to handle file I/O for C++
@@ -125,13 +129,13 @@ public:
 }; //! class IOStream
 
 // ----------------------------------------------------------------------------------
-inline
+AI_FORCE_INLINE
 IOStream::IOStream() AI_NO_EXCEPT {
     // empty
 }
 
 // ----------------------------------------------------------------------------------
-inline
+AI_FORCE_INLINE
 IOStream::~IOStream() {
     // empty
 }
diff --git a/include/assimp/IOStreamBuffer.h b/include/assimp/IOStreamBuffer.h
index 58abd97a0..97c84b23e 100644
--- a/include/assimp/IOStreamBuffer.h
+++ b/include/assimp/IOStreamBuffer.h
@@ -1,5 +1,3 @@
-#pragma once
-
 /*
 Open Asset Import Library (assimp)
 ----------------------------------------------------------------------
@@ -42,10 +40,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------
 */
 
+#pragma once
+#ifndef AI_IOSTREAMBUFFER_H_INC
+#define AI_IOSTREAMBUFFER_H_INC
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
 #include <assimp/IOStream.hpp>
-
-#include "ParsingUtils.h"
+#include <assimp/ParsingUtils.h>
 
 #include <vector>
 
@@ -124,7 +129,7 @@ private:
 };
 
 template<class T>
-inline
+AI_FORCE_INLINE
 IOStreamBuffer<T>::IOStreamBuffer( size_t cache )
 : m_stream( nullptr )
 , m_filesize( 0 )
@@ -138,13 +143,13 @@ IOStreamBuffer<T>::IOStreamBuffer( size_t cache )
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 IOStreamBuffer<T>::~IOStreamBuffer() {
     // empty
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::open( IOStream *stream ) {
     //  file still opened!
     if ( nullptr != m_stream ) {
@@ -174,7 +179,7 @@ bool IOStreamBuffer<T>::open( IOStream *stream ) {
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::close() {
     if ( nullptr == m_stream ) {
         return false;
@@ -192,19 +197,19 @@ bool IOStreamBuffer<T>::close() {
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 size_t IOStreamBuffer<T>::size() const {
     return m_filesize;
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 size_t IOStreamBuffer<T>::cacheSize() const {
     return m_cacheSize;
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::readNextBlock() {
     m_stream->Seek( m_filePos, aiOrigin_SET );
     size_t readLen = m_stream->Read( &m_cache[ 0 ], sizeof( T ), m_cacheSize );
@@ -222,25 +227,25 @@ bool IOStreamBuffer<T>::readNextBlock() {
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 size_t IOStreamBuffer<T>::getNumBlocks() const {
     return m_numBlocks;
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 size_t IOStreamBuffer<T>::getCurrentBlockIndex() const {
     return m_blockIdx;
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 size_t IOStreamBuffer<T>::getFilePos() const {
     return m_filePos;
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::getNextDataLine( std::vector<T> &buffer, T continuationToken ) {
     buffer.resize( m_cacheSize );
     if ( m_cachePos >= m_cacheSize || 0 == m_filePos ) {
@@ -289,13 +294,13 @@ bool IOStreamBuffer<T>::getNextDataLine( std::vector<T> &buffer, T continuationT
     return true;
 }
 
-static inline
+static AI_FORCE_INLINE
 bool isEndOfCache( size_t pos, size_t cacheSize ) {
     return ( pos == cacheSize );
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::getNextLine(std::vector<T> &buffer) {
     buffer.resize(m_cacheSize);
     if ( isEndOfCache( m_cachePos, m_cacheSize ) || 0 == m_filePos) {
@@ -335,7 +340,7 @@ bool IOStreamBuffer<T>::getNextLine(std::vector<T> &buffer) {
 }
 
 template<class T>
-inline
+AI_FORCE_INLINE
 bool IOStreamBuffer<T>::getNextBlock( std::vector<T> &buffer) {
     // Return the last block-value if getNextLine was used before
     if ( 0 != m_cachePos ) {      
@@ -353,3 +358,5 @@ bool IOStreamBuffer<T>::getNextBlock( std::vector<T> &buffer) {
 }
 
 } // !ns Assimp
+
+#endif // AI_IOSTREAMBUFFER_H_INC
diff --git a/include/assimp/IOSystem.hpp b/include/assimp/IOSystem.hpp
index 78139c283..f1fb3b0c2 100644
--- a/include/assimp/IOSystem.hpp
+++ b/include/assimp/IOSystem.hpp
@@ -50,6 +50,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_IOSYSTEM_H_INC
 #define AI_IOSYSTEM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifndef __cplusplus
 #   error This header requires C++ to be used. aiFileIO.h is the \
     corresponding C interface.
diff --git a/include/assimp/Importer.hpp b/include/assimp/Importer.hpp
index 4941df412..bf449a9a2 100644
--- a/include/assimp/Importer.hpp
+++ b/include/assimp/Importer.hpp
@@ -48,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_ASSIMP_HPP_INC
 #define AI_ASSIMP_HPP_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifndef __cplusplus
 #   error This header requires C++ to be used. Use assimp.h for plain C.
 #endif // __cplusplus
diff --git a/include/assimp/LineSplitter.h b/include/assimp/LineSplitter.h
index 4afe45b92..6c1097bb6 100644
--- a/include/assimp/LineSplitter.h
+++ b/include/assimp/LineSplitter.h
@@ -48,9 +48,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef INCLUDED_LINE_SPLITTER_H
 #define INCLUDED_LINE_SPLITTER_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <stdexcept>
-#include "StreamReader.h"
-#include "ParsingUtils.h"
+#include <assimp/StreamReader.h>
+#include <assimp/ParsingUtils.h>
 
 namespace Assimp {
 
@@ -140,7 +144,7 @@ private:
     bool mSwallow, mSkip_empty_lines, mTrim;
 };
 
-inline
+AI_FORCE_INLINE
 LineSplitter::LineSplitter(StreamReaderLE& stream, bool skip_empty_lines, bool trim )
 : mIdx(0)
 , mCur()
@@ -153,12 +157,12 @@ LineSplitter::LineSplitter(StreamReaderLE& stream, bool skip_empty_lines, bool t
     mIdx = 0;
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter::~LineSplitter() {
     // empty
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter& LineSplitter::operator++() {
     if (mSwallow) {
         mSwallow = false;
@@ -199,12 +203,12 @@ LineSplitter& LineSplitter::operator++() {
     return *this;
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter &LineSplitter::operator++(int) {
     return ++(*this);
 }
 
-inline
+AI_FORCE_INLINE
 const char *LineSplitter::operator[] (size_t idx) const {
     const char* s = operator->()->c_str();
 
@@ -222,7 +226,7 @@ const char *LineSplitter::operator[] (size_t idx) const {
 }
 
 template <size_t N>
-inline
+AI_FORCE_INLINE
 void LineSplitter::get_tokens(const char* (&tokens)[N]) const {
     const char* s = operator->()->c_str();
 
@@ -238,44 +242,44 @@ void LineSplitter::get_tokens(const char* (&tokens)[N]) const {
     }
 }
 
-inline
+AI_FORCE_INLINE
 const std::string* LineSplitter::operator -> () const {
     return &mCur;
 }
 
-inline
+AI_FORCE_INLINE
 std::string LineSplitter::operator* () const {
     return mCur;
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter::operator bool() const {
     return mStream.GetRemainingSize() > 0;
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter::operator line_idx() const {
     return mIdx;
 }
 
-inline
+AI_FORCE_INLINE
 LineSplitter::line_idx LineSplitter::get_index() const {
     return mIdx;
 }
 
-inline
+AI_FORCE_INLINE
 StreamReaderLE &LineSplitter::get_stream() {
     return mStream;
 }
 
-inline
+AI_FORCE_INLINE
 bool LineSplitter::match_start(const char* check) {
     const size_t len = ::strlen(check);
 
     return len <= mCur.length() && std::equal(check, check + len, mCur.begin());
 }
 
-inline
+AI_FORCE_INLINE
 void LineSplitter::swallow_next_increment() {
     mSwallow = true;
 }
diff --git a/include/assimp/LogAux.h b/include/assimp/LogAux.h
index 558485272..bcead78dd 100644
--- a/include/assimp/LogAux.h
+++ b/include/assimp/LogAux.h
@@ -43,9 +43,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file  LogAux.h
  *  @brief Common logging usage patterns for importer implementations
  */
+#pragma once
 #ifndef INCLUDED_AI_LOGAUX_H
 #define INCLUDED_AI_LOGAUX_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/TinyFormatter.h>
 #include <assimp/Exceptional.h>
 #include <assimp/DefaultLogger.hpp>
diff --git a/include/assimp/Macros.h b/include/assimp/Macros.h
deleted file mode 100644
index 651530337..000000000
--- a/include/assimp/Macros.h
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
----------------------------------------------------------------------------
-Open Asset Import Library (assimp)
----------------------------------------------------------------------------
-
-Copyright (c) 2006-2019, assimp team
-
-All rights reserved.
-
-Redistribution and use of this software in source and binary forms,
-with or without modification, are permitted provided that the following
-conditions are met:
-
-* Redistributions of source code must retain the above
-  copyright notice, this list of conditions and the
-  following disclaimer.
-
-* Redistributions in binary form must reproduce the above
-  copyright notice, this list of conditions and the
-  following disclaimer in the documentation and/or other
-  materials provided with the distribution.
-
-* Neither the name of the assimp team, nor the names of its
-  contributors may be used to endorse or promote products
-  derived from this software without specific prior
-  written permission of the assimp team.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
----------------------------------------------------------------------------
-*/
-
-/* Helper macro to set a pointer to NULL in debug builds
- */
-#if (defined ASSIMP_BUILD_DEBUG)
-#   define AI_DEBUG_INVALIDATE_PTR(x) x = NULL;
-#else
-#   define AI_DEBUG_INVALIDATE_PTR(x)
-#endif
-
diff --git a/include/assimp/MathFunctions.h b/include/assimp/MathFunctions.h
index f49273bb3..b6c5872a7 100644
--- a/include/assimp/MathFunctions.h
+++ b/include/assimp/MathFunctions.h
@@ -41,6 +41,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #pragma once
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 /** @file  MathFunctions.h
 *  @brief Implementation of math utility functions.
  *
diff --git a/include/assimp/MemoryIOWrapper.h b/include/assimp/MemoryIOWrapper.h
index c52278718..5598d4fc5 100644
--- a/include/assimp/MemoryIOWrapper.h
+++ b/include/assimp/MemoryIOWrapper.h
@@ -42,12 +42,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /** @file MemoryIOWrapper.h
  *  Handy IOStream/IOSystem implemetation to read directly from a memory buffer */
+#pragma once
 #ifndef AI_MEMORYIOSTREAM_H_INC
 #define AI_MEMORYIOSTREAM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/IOStream.hpp>
 #include <assimp/IOSystem.hpp>
 #include <assimp/ai_assert.h>
+
 #include <stdint.h>
 
 namespace Assimp    {
diff --git a/include/assimp/ParsingUtils.h b/include/assimp/ParsingUtils.h
index 6b9574fc6..302560124 100644
--- a/include/assimp/ParsingUtils.h
+++ b/include/assimp/ParsingUtils.h
@@ -44,11 +44,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file ParsingUtils.h
  *  @brief Defines helper functions for text parsing
  */
+#pragma once
 #ifndef AI_PARSING_UTILS_H_INC
 #define AI_PARSING_UTILS_H_INC
 
-#include "StringComparison.h"
-#include "StringUtils.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/StringComparison.h>
+#include <assimp/StringUtils.h>
 #include <assimp/defs.h>
 
 namespace Assimp {
diff --git a/include/assimp/Profiler.h b/include/assimp/Profiler.h
index 6ff9d41c0..624029be9 100644
--- a/include/assimp/Profiler.h
+++ b/include/assimp/Profiler.h
@@ -43,12 +43,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file Profiler.h
  *  @brief Utility to measure the respective runtime of each import step
  */
-#ifndef INCLUDED_PROFILER_H
-#define INCLUDED_PROFILER_H
+#pragma once
+#ifndef AI_INCLUDED_PROFILER_H
+#define AI_INCLUDED_PROFILER_H
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
 
 #include <chrono>
 #include <assimp/DefaultLogger.hpp>
-#include "TinyFormatter.h"
+#include <assimp/TinyFormatter.h>
 
 #include <map>
 
@@ -67,7 +72,6 @@ public:
         // empty
     }
 
-public:
 
     /** Start a named timer */
     void BeginRegion(const std::string& region) {
@@ -95,5 +99,5 @@ private:
 }
 }
 
-#endif
+#endif // AI_INCLUDED_PROFILER_H
 
diff --git a/include/assimp/ProgressHandler.hpp b/include/assimp/ProgressHandler.hpp
index 4e47f1d0a..8991a6461 100644
--- a/include/assimp/ProgressHandler.hpp
+++ b/include/assimp/ProgressHandler.hpp
@@ -47,9 +47,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_PROGRESSHANDLER_H_INC
 #define AI_PROGRESSHANDLER_H_INC
 
-#include "types.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
 
-namespace Assimp    {
+#include <assimp/types.h>
+
+namespace Assimp {
 
 // ------------------------------------------------------------------------------------
 /** @brief CPP-API: Abstract interface for custom progress report receivers.
diff --git a/include/assimp/RemoveComments.h b/include/assimp/RemoveComments.h
index 404b49671..f12942053 100644
--- a/include/assimp/RemoveComments.h
+++ b/include/assimp/RemoveComments.h
@@ -4,7 +4,6 @@ Open Asset Import Library (assimp)
 
 Copyright (c) 2006-2019, assimp team
 
-
 All rights reserved.
 
 Redistribution and use of this software in source and binary forms,
@@ -43,9 +42,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file Declares a helper class, "CommentRemover", which can be
  *  used to remove comments (single and multi line) from a text file.
  */
+#pragma once
 #ifndef AI_REMOVE_COMMENTS_H_INC
 #define AI_REMOVE_COMMENTS_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
 
 #include <assimp/defs.h>
 
@@ -58,8 +61,7 @@ namespace Assimp    {
  *  to those in C or C++ so this code has been moved to a separate
  *  module.
  */
-class ASSIMP_API CommentRemover
-{
+class ASSIMP_API CommentRemover {
     // class cannot be instanced
     CommentRemover() {}
 
diff --git a/include/assimp/SGSpatialSort.h b/include/assimp/SGSpatialSort.h
index 5b4f3f41f..fdb5ce817 100644
--- a/include/assimp/SGSpatialSort.h
+++ b/include/assimp/SGSpatialSort.h
@@ -42,9 +42,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /** Small helper classes to optimize finding vertices close to a given location
  */
+#pragma once
 #ifndef AI_D3DSSPATIALSORT_H_INC
 #define AI_D3DSSPATIALSORT_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
 #include <vector>
 #include <stdint.h>
diff --git a/include/assimp/SceneCombiner.h b/include/assimp/SceneCombiner.h
index e594f649f..0683c1e05 100644
--- a/include/assimp/SceneCombiner.h
+++ b/include/assimp/SceneCombiner.h
@@ -43,17 +43,22 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file Declares a helper class, "SceneCombiner" providing various
  *  utilities to merge scenes.
  */
+#pragma once
 #ifndef AI_SCENE_COMBINER_H_INC
 #define AI_SCENE_COMBINER_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/ai_assert.h>
 #include <assimp/types.h>
 #include <assimp/Defines.h>
+
 #include <stddef.h>
 #include <set>
 #include <list>
 #include <stdint.h>
-
 #include <vector>
 
 struct aiScene;
diff --git a/include/assimp/SkeletonMeshBuilder.h b/include/assimp/SkeletonMeshBuilder.h
index f9b8d9f55..ad979a33f 100644
--- a/include/assimp/SkeletonMeshBuilder.h
+++ b/include/assimp/SkeletonMeshBuilder.h
@@ -47,9 +47,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *  for animation skeletons.
  */
 
+#pragma once
 #ifndef AI_SKELETONMESHBUILDER_H_INC
 #define AI_SKELETONMESHBUILDER_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <vector>
 #include <assimp/mesh.h>
 
diff --git a/include/assimp/SmoothingGroups.h b/include/assimp/SmoothingGroups.h
index 92d65cea0..c1a93947f 100644
--- a/include/assimp/SmoothingGroups.h
+++ b/include/assimp/SmoothingGroups.h
@@ -43,10 +43,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file Defines the helper data structures for importing 3DS files.
 http://www.jalix.org/ressources/graphics/3DS/_unofficials/3ds-unofficial.txt */
 
+#pragma once
 #ifndef AI_SMOOTHINGGROUPS_H_INC
 #define AI_SMOOTHINGGROUPS_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/vector3.h>
+
 #include <stdint.h>
 #include <vector>
 
diff --git a/include/assimp/SmoothingGroups.inl b/include/assimp/SmoothingGroups.inl
index 84ea4a1b0..37ea083db 100644
--- a/include/assimp/SmoothingGroups.inl
+++ b/include/assimp/SmoothingGroups.inl
@@ -41,13 +41,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /** @file Generation of normal vectors basing on smoothing groups */
 
+#pragma once
 #ifndef AI_SMOOTHINGGROUPS_INL_INCLUDED
 #define AI_SMOOTHINGGROUPS_INL_INCLUDED
 
-// internal headers
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/SGSpatialSort.h>
 
-// CRT header
 #include <algorithm>
 
 using namespace Assimp;
diff --git a/include/assimp/SpatialSort.h b/include/assimp/SpatialSort.h
index 61b345bcb..9f9354315 100644
--- a/include/assimp/SpatialSort.h
+++ b/include/assimp/SpatialSort.h
@@ -41,9 +41,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /** Small helper classes to optimise finding vertizes close to a given location */
+#pragma once
 #ifndef AI_SPATIALSORT_H_INC
 #define AI_SPATIALSORT_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <vector>
 #include <assimp/types.h>
 
diff --git a/include/assimp/StandardShapes.h b/include/assimp/StandardShapes.h
index 3791569b8..c594cb63f 100644
--- a/include/assimp/StandardShapes.h
+++ b/include/assimp/StandardShapes.h
@@ -41,11 +41,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /** @file Declares a helper class, "StandardShapes" which generates
- *  vertices for standard shapes, such as cylnders, cones, spheres ..
+ *  vertices for standard shapes, such as cylinders, cones, spheres ..
  */
+#pragma once
 #ifndef AI_STANDARD_SHAPES_H_INC
 #define AI_STANDARD_SHAPES_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/vector3.h>
 #include <vector>
 
diff --git a/include/assimp/StreamReader.h b/include/assimp/StreamReader.h
index 9116c1426..cb24f1595 100644
--- a/include/assimp/StreamReader.h
+++ b/include/assimp/StreamReader.h
@@ -44,15 +44,19 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file Defines the StreamReader class which reads data from
  *  a binary stream with a well-defined endianness.
  */
-
+#pragma once
 #ifndef AI_STREAMREADER_H_INCLUDED
 #define AI_STREAMREADER_H_INCLUDED
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/IOStream.hpp>
 #include <assimp/Defines.h>
+#include <assimp/ByteSwapper.h>
+#include <assimp/Exceptional.h>
 
-#include "ByteSwapper.h"
-#include "Exceptional.h"
 #include <memory>
 
 namespace Assimp {
diff --git a/include/assimp/StreamWriter.h b/include/assimp/StreamWriter.h
index c7cf6c0d7..489e8adfe 100644
--- a/include/assimp/StreamWriter.h
+++ b/include/assimp/StreamWriter.h
@@ -43,11 +43,15 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 /** @file Defines the StreamWriter class which writes data to
  *  a binary stream with a well-defined endianness. */
-
+#pragma once
 #ifndef AI_STREAMWRITER_H_INCLUDED
 #define AI_STREAMWRITER_H_INCLUDED
 
-#include "ByteSwapper.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/ByteSwapper.h>
 #include <assimp/IOStream.hpp>
 
 #include <memory>
diff --git a/include/assimp/StringComparison.h b/include/assimp/StringComparison.h
index 8acef277b..d3ca3e971 100644
--- a/include/assimp/StringComparison.h
+++ b/include/assimp/StringComparison.h
@@ -49,12 +49,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    These functions are not consistently available on all platforms,
    or the provided implementations behave too differently.
 */
+#pragma once
 #ifndef INCLUDED_AI_STRING_WORKERS_H
 #define INCLUDED_AI_STRING_WORKERS_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/ai_assert.h>
 #include <assimp/defs.h>
-#include "StringComparison.h"
+#include <assimp/StringComparison.h>
 
 #include <string.h>
 #include <stdint.h>
diff --git a/include/assimp/StringUtils.h b/include/assimp/StringUtils.h
index d68b7fa47..af481f819 100644
--- a/include/assimp/StringUtils.h
+++ b/include/assimp/StringUtils.h
@@ -39,9 +39,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----------------------------------------------------------------------
 */
+#pragma once
 #ifndef INCLUDED_AI_STRINGUTILS_H
 #define INCLUDED_AI_STRINGUTILS_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/defs.h>
 
 #include <sstream>
diff --git a/include/assimp/Subdivision.h b/include/assimp/Subdivision.h
index 43feb73b3..e9450267e 100644
--- a/include/assimp/Subdivision.h
+++ b/include/assimp/Subdivision.h
@@ -45,7 +45,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_SUBDISIVION_H_INC
 #define AI_SUBDISIVION_H_INC
 
-#include <cstddef>
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
 
 struct aiMesh;
diff --git a/include/assimp/TinyFormatter.h b/include/assimp/TinyFormatter.h
index 1226b482e..6227e42c5 100644
--- a/include/assimp/TinyFormatter.h
+++ b/include/assimp/TinyFormatter.h
@@ -45,9 +45,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *    to get rid of the boost::format dependency. Much slinker,
  *    basically just extends stringstream.
  */
+#pragma once
 #ifndef INCLUDED_TINY_FORMATTER_H
 #define INCLUDED_TINY_FORMATTER_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <sstream>
 
 namespace Assimp {
@@ -65,24 +70,15 @@ namespace Formatter {
  *  @endcode */
 template < typename T,
     typename CharTraits = std::char_traits<T>,
-    typename Allocator  = std::allocator<T>
->
-class basic_formatter
-{
-
+    typename Allocator  = std::allocator<T> >
+class basic_formatter {
 public:
+    typedef class std::basic_string<T,CharTraits,Allocator> string;
+    typedef class std::basic_ostringstream<T,CharTraits,Allocator> stringstream;
 
-    typedef class std::basic_string<
-        T,CharTraits,Allocator
-    > string;
-
-    typedef class std::basic_ostringstream<
-        T,CharTraits,Allocator
-    > stringstream;
-
-public:
-
-    basic_formatter() {}
+    basic_formatter() {
+        // empty
+    }
 
     /* Allow basic_formatter<T>'s to be used almost interchangeably
      * with std::(w)string or const (w)char* arguments because the
@@ -104,14 +100,10 @@ public:
     }
 #endif
 
-
-public:
-
     operator string () const {
         return underlying.str();
     }
 
-
     /* note - this is declared const because binding temporaries does only
      * work for const references, so many function prototypes will
      * include const basic_formatter<T>& s but might still want to
diff --git a/include/assimp/Vertex.h b/include/assimp/Vertex.h
index 2a7f0256a..5e63db5fe 100644
--- a/include/assimp/Vertex.h
+++ b/include/assimp/Vertex.h
@@ -47,12 +47,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   that are not currently well-defined (and would cause compile errors
   due to missing operators in the math library), are commented.
   */
+#pragma once
 #ifndef AI_VERTEX_H_INC
 #define AI_VERTEX_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/vector3.h>
 #include <assimp/mesh.h>
 #include <assimp/ai_assert.h>
+
 #include <functional>
 
 namespace Assimp    {
@@ -91,23 +97,14 @@ namespace Assimp    {
  *  to *all* vertex components equally. This is useful for stuff like interpolation
  *  or subdivision, but won't work if special handling is required for some vertex components. */
 // ------------------------------------------------------------------------------------------------
-class Vertex
-{
+class Vertex {
     friend Vertex operator + (const Vertex&,const Vertex&);
     friend Vertex operator - (const Vertex&,const Vertex&);
-
-//  friend Vertex operator + (const Vertex&,ai_real);
-//  friend Vertex operator - (const Vertex&,ai_real);
     friend Vertex operator * (const Vertex&,ai_real);
     friend Vertex operator / (const Vertex&,ai_real);
-
-//  friend Vertex operator + (ai_real, const Vertex&);
-//  friend Vertex operator - (ai_real, const Vertex&);
     friend Vertex operator * (ai_real, const Vertex&);
-//  friend Vertex operator / (ai_real, const Vertex&);
 
 public:
-
     Vertex() {}
 
     // ----------------------------------------------------------------------------
@@ -158,8 +155,6 @@ public:
         }
     }
 
-public:
-
     Vertex& operator += (const Vertex& v) {
         *this = *this+v;
         return *this;
@@ -170,18 +165,6 @@ public:
         return *this;
     }
 
-
-/*
-    Vertex& operator += (ai_real v) {
-        *this = *this+v;
-        return *this;
-    }
-
-    Vertex& operator -= (ai_real v) {
-        *this = *this-v;
-        return *this;
-    }
-*/
     Vertex& operator *= (ai_real v) {
         *this = *this*v;
         return *this;
@@ -192,12 +175,9 @@ public:
         return *this;
     }
 
-public:
-
     // ----------------------------------------------------------------------------
     /** Convert back to non-interleaved storage */
     void SortBack(aiMesh* out, unsigned int idx) const {
-
         ai_assert(idx<out->mNumVertices);
         out->mVertices[idx] = position;
 
@@ -291,8 +271,6 @@ public:
     aiColor4D colors[AI_MAX_NUMBER_OF_COLOR_SETS];
 };
 
-
-
 // ------------------------------------------------------------------------------------------------
 AI_FORCE_INLINE Vertex operator + (const Vertex& v0,const Vertex& v1) {
     return Vertex::BinaryOp<std::plus>(v0,v1);
@@ -302,19 +280,6 @@ AI_FORCE_INLINE Vertex operator - (const Vertex& v0,const Vertex& v1) {
     return Vertex::BinaryOp<std::minus>(v0,v1);
 }
 
-
-// ------------------------------------------------------------------------------------------------
-/*
-AI_FORCE_INLINE Vertex operator + (const Vertex& v0,ai_real f) {
-    return Vertex::BinaryOp<Intern::plus>(v0,f);
-}
-
-AI_FORCE_INLINE Vertex operator - (const Vertex& v0,ai_real f) {
-    return Vertex::BinaryOp<Intern::minus>(v0,f);
-}
-
-*/
-
 AI_FORCE_INLINE Vertex operator * (const Vertex& v0,ai_real f) {
     return Vertex::BinaryOp<Intern::multiplies>(v0,f);
 }
@@ -323,26 +288,10 @@ AI_FORCE_INLINE Vertex operator / (const Vertex& v0,ai_real f) {
     return Vertex::BinaryOp<Intern::multiplies>(v0,1.f/f);
 }
 
-// ------------------------------------------------------------------------------------------------
-/*
-AI_FORCE_INLINE Vertex operator + (ai_real f,const Vertex& v0) {
-    return Vertex::BinaryOp<Intern::plus>(f,v0);
-}
-
-AI_FORCE_INLINE Vertex operator - (ai_real f,const Vertex& v0) {
-    return Vertex::BinaryOp<Intern::minus>(f,v0);
-}
-*/
-
 AI_FORCE_INLINE Vertex operator * (ai_real f,const Vertex& v0) {
     return Vertex::BinaryOp<Intern::multiplies>(f,v0);
 }
 
-/*
-AI_FORCE_INLINE Vertex operator / (ai_real f,const Vertex& v0) {
-    return Vertex::BinaryOp<Intern::divides>(f,v0);
 }
-*/
 
-}
-#endif
+#endif // AI_VERTEX_H_INC
diff --git a/include/assimp/XMLTools.h b/include/assimp/XMLTools.h
index b0d327687..95f12cdeb 100644
--- a/include/assimp/XMLTools.h
+++ b/include/assimp/XMLTools.h
@@ -40,9 +40,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----------------------------------------------------------------------
 */
 
+#pragma once
 #ifndef INCLUDED_ASSIMP_XML_TOOLS_H
 #define INCLUDED_ASSIMP_XML_TOOLS_H
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <string>
 
 namespace Assimp {
diff --git a/include/assimp/ZipArchiveIOSystem.h b/include/assimp/ZipArchiveIOSystem.h
index 38cbbf2a7..516ea84de 100644
--- a/include/assimp/ZipArchiveIOSystem.h
+++ b/include/assimp/ZipArchiveIOSystem.h
@@ -45,43 +45,50 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *  @brief Implementation of IOSystem to read a ZIP file from another IOSystem
 */
 
+#pragma once
 #ifndef AI_ZIPARCHIVEIOSYSTEM_H_INC
 #define AI_ZIPARCHIVEIOSYSTEM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/IOStream.hpp>
 #include <assimp/IOSystem.hpp>
 
 namespace Assimp {
-    class ZipArchiveIOSystem : public IOSystem {
-    public:
-        //! Open a Zip using the proffered IOSystem
-        ZipArchiveIOSystem(IOSystem* pIOHandler, const char *pFilename, const char* pMode = "r");
-        ZipArchiveIOSystem(IOSystem* pIOHandler, const std::string& rFilename, const char* pMode = "r");
-        virtual ~ZipArchiveIOSystem();
-        bool Exists(const char* pFilename) const override;
-        char getOsSeparator() const override;
-        IOStream* Open(const char* pFilename, const char* pMode = "rb") override;
-        void Close(IOStream* pFile) override;
 
-        // Specific to ZIP
-        //! The file was opened and is a ZIP
-        bool isOpen() const;
+class ZipArchiveIOSystem : public IOSystem {
+public:
+    //! Open a Zip using the proffered IOSystem
+    ZipArchiveIOSystem(IOSystem* pIOHandler, const char *pFilename, const char* pMode = "r");
+    ZipArchiveIOSystem(IOSystem* pIOHandler, const std::string& rFilename, const char* pMode = "r");
+    virtual ~ZipArchiveIOSystem();
+    bool Exists(const char* pFilename) const override;
+    char getOsSeparator() const override;
+    IOStream* Open(const char* pFilename, const char* pMode = "rb") override;
+    void Close(IOStream* pFile) override;
 
-        //! Get the list of all files with their simplified paths
-        //! Intended for use within Assimp library boundaries
-        void getFileList(std::vector<std::string>& rFileList) const;
+    // Specific to ZIP
+    //! The file was opened and is a ZIP
+    bool isOpen() const;
 
-        //! Get the list of all files with extension (must be lowercase)
-        //! Intended for use within Assimp library boundaries
-        void getFileListExtension(std::vector<std::string>& rFileList, const std::string& extension) const;
+    //! Get the list of all files with their simplified paths
+    //! Intended for use within Assimp library boundaries
+    void getFileList(std::vector<std::string>& rFileList) const;
 
-        static bool isZipArchive(IOSystem* pIOHandler, const char *pFilename);
-        static bool isZipArchive(IOSystem* pIOHandler, const std::string& rFilename);
+    //! Get the list of all files with extension (must be lowercase)
+    //! Intended for use within Assimp library boundaries
+    void getFileListExtension(std::vector<std::string>& rFileList, const std::string& extension) const;
+
+    static bool isZipArchive(IOSystem* pIOHandler, const char *pFilename);
+    static bool isZipArchive(IOSystem* pIOHandler, const std::string& rFilename);
+
+private:
+    class Implement;
+    Implement *pImpl = nullptr;
+};
 
-    private:
-        class Implement;
-        Implement *pImpl = nullptr;
-    };
 } // Namespace Assimp
 
 #endif // AI_ZIPARCHIVEIOSYSTEM_H_INC
diff --git a/include/assimp/aabb.h b/include/assimp/aabb.h
index a20f31742..83bb62256 100644
--- a/include/assimp/aabb.h
+++ b/include/assimp/aabb.h
@@ -5,8 +5,6 @@ Open Asset Import Library (assimp)
 
 Copyright (c) 2006-2019, assimp team
 
-
-
 All rights reserved.
 
 Redistribution and use of this software in source and binary forms,
@@ -45,6 +43,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_AABB_H_INC
 #define AI_AABB_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/vector3.h>
 
 struct aiAABB {
@@ -69,8 +71,9 @@ struct aiAABB {
         // empty
     }
 
-#endif 
+#endif // __cplusplus
+
 };
 
 
-#endif
+#endif // AI_AABB_H_INC
diff --git a/include/assimp/ai_assert.h b/include/assimp/ai_assert.h
index e5de5d3f3..2b32b01d3 100644
--- a/include/assimp/ai_assert.h
+++ b/include/assimp/ai_assert.h
@@ -44,6 +44,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_ASSERT_H_INC
 #define AI_ASSERT_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef ASSIMP_BUILD_DEBUG
 #   include <assert.h>
 #   define ai_assert(expression) assert( expression )
diff --git a/include/assimp/anim.h b/include/assimp/anim.h
index 02e92739e..e208b11ad 100644
--- a/include/assimp/anim.h
+++ b/include/assimp/anim.h
@@ -50,6 +50,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_ANIM_H_INC
 #define AI_ANIM_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
 #include <assimp/quaternion.h>
 
diff --git a/include/assimp/camera.h b/include/assimp/camera.h
index a9a9f7653..adb749ff5 100644
--- a/include/assimp/camera.h
+++ b/include/assimp/camera.h
@@ -47,6 +47,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_CAMERA_H_INC
 #define AI_CAMERA_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include "types.h"
 
 #ifdef __cplusplus
diff --git a/include/assimp/cexport.h b/include/assimp/cexport.h
index 1d62dc26b..cbc0253d5 100644
--- a/include/assimp/cexport.h
+++ b/include/assimp/cexport.h
@@ -3,7 +3,7 @@
 Open Asset Import Library (assimp)
 ---------------------------------------------------------------------------
 
-Copyright (c) 2006-2011, assimp team
+Copyright (c) 2006-2019, assimp team
 
 All rights reserved.
 
@@ -46,6 +46,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_EXPORT_H_INC
 #define AI_EXPORT_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifndef ASSIMP_BUILD_NO_EXPORT
 
 // Public ASSIMP data structures
diff --git a/include/assimp/cfileio.h b/include/assimp/cfileio.h
index 8f7ca4546..be90999d8 100644
--- a/include/assimp/cfileio.h
+++ b/include/assimp/cfileio.h
@@ -48,10 +48,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_FILEIO_H_INC
 #define AI_FILEIO_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
+
 struct aiFileIO;
 struct aiFile;
 
diff --git a/include/assimp/cimport.h b/include/assimp/cimport.h
index dbd10f137..66b1c9a17 100644
--- a/include/assimp/cimport.h
+++ b/include/assimp/cimport.h
@@ -48,8 +48,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_ASSIMP_H_INC
 #define AI_ASSIMP_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
-#include "importerdesc.h"
+#include <assimp/importerdesc.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/assimp/color4.h b/include/assimp/color4.h
index 3c97c8eda..fa86128f4 100644
--- a/include/assimp/color4.h
+++ b/include/assimp/color4.h
@@ -47,7 +47,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_COLOR4D_H_INC
 #define AI_COLOR4D_H_INC
 
-#include "defs.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/defs.h>
 
 #ifdef __cplusplus
 
@@ -56,8 +60,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *   alpha component. Color values range from 0 to 1. */
 // ----------------------------------------------------------------------------------
 template <typename TReal>
-class aiColor4t
-{
+class aiColor4t {
 public:
     aiColor4t() AI_NO_EXCEPT : r(), g(), b(), a() {}
     aiColor4t (TReal _r, TReal _g, TReal _b, TReal _a)
@@ -65,14 +68,12 @@ public:
     explicit aiColor4t (TReal _r) : r(_r), g(_r), b(_r), a(_r) {}
     aiColor4t (const aiColor4t& o) = default;
 
-public:
     // combined operators
     const aiColor4t& operator += (const aiColor4t& o);
     const aiColor4t& operator -= (const aiColor4t& o);
     const aiColor4t& operator *= (TReal f);
     const aiColor4t& operator /= (TReal f);
 
-public:
     // comparison
     bool operator == (const aiColor4t& other) const;
     bool operator != (const aiColor4t& other) const;
@@ -85,8 +86,6 @@ public:
     /** check whether a color is (close to) black */
     inline bool IsBlack() const;
 
-public:
-
     // Red, green, blue and alpha color values
     TReal r, g, b, a;
 };  // !struct aiColor4D
diff --git a/include/assimp/color4.inl b/include/assimp/color4.inl
index afa53dcb5..d4a2a9810 100644
--- a/include/assimp/color4.inl
+++ b/include/assimp/color4.inl
@@ -48,36 +48,61 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_COLOR4D_INL_INC
 #define AI_COLOR4D_INL_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef __cplusplus
-#include "color4.h"
+#include <assimp/color4.h>
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE const aiColor4t<TReal>& aiColor4t<TReal>::operator += (const aiColor4t<TReal>& o) {
-    r += o.r; g += o.g; b += o.b; a += o.a;
+AI_FORCE_INLINE
+const aiColor4t<TReal>& aiColor4t<TReal>::operator += (const aiColor4t<TReal>& o) {
+    r += o.r;
+    g += o.g;
+    b += o.b;
+    a += o.a;
+
     return *this;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE const aiColor4t<TReal>& aiColor4t<TReal>::operator -= (const aiColor4t<TReal>& o) {
-    r -= o.r; g -= o.g; b -= o.b; a -= o.a;
+AI_FORCE_INLINE
+const aiColor4t<TReal>& aiColor4t<TReal>::operator -= (const aiColor4t<TReal>& o) {
+    r -= o.r;
+    g -= o.g;
+    b -= o.b;
+    a -= o.a;
+
     return *this;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE const aiColor4t<TReal>& aiColor4t<TReal>::operator *= (TReal f) {
-    r *= f; g *= f; b *= f; a *= f;
+AI_FORCE_INLINE
+const aiColor4t<TReal>& aiColor4t<TReal>::operator *= (TReal f) {
+    r *= f;
+    g *= f;
+    b *= f;
+    a *= f;
+
     return *this;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE const aiColor4t<TReal>& aiColor4t<TReal>::operator /= (TReal f) {
-    r /= f; g /= f; b /= f; a /= f;
+AI_FORCE_INLINE
+const aiColor4t<TReal>& aiColor4t<TReal>::operator /= (TReal f) {
+    r /= f;
+    g /= f;
+    b /= f;
+    a /= f;
+
     return *this;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE TReal aiColor4t<TReal>::operator[](unsigned int i) const {
+AI_FORCE_INLINE
+TReal aiColor4t<TReal>::operator[](unsigned int i) const {
     switch ( i ) {
         case 0:
             return r;
@@ -94,7 +119,8 @@ AI_FORCE_INLINE TReal aiColor4t<TReal>::operator[](unsigned int i) const {
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE TReal& aiColor4t<TReal>::operator[](unsigned int i) {
+AI_FORCE_INLINE
+TReal& aiColor4t<TReal>::operator[](unsigned int i) {
     switch ( i ) {
         case 0:
             return r;
@@ -111,17 +137,20 @@ AI_FORCE_INLINE TReal& aiColor4t<TReal>::operator[](unsigned int i) {
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE bool aiColor4t<TReal>::operator== (const aiColor4t<TReal>& other) const {
+AI_FORCE_INLINE
+bool aiColor4t<TReal>::operator== (const aiColor4t<TReal>& other) const {
     return r == other.r && g == other.g && b == other.b && a == other.a;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE bool aiColor4t<TReal>::operator!= (const aiColor4t<TReal>& other) const {
+AI_FORCE_INLINE
+bool aiColor4t<TReal>::operator!= (const aiColor4t<TReal>& other) const {
     return r != other.r || g != other.g || b != other.b || a != other.a;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE bool aiColor4t<TReal>::operator< (const aiColor4t<TReal>& other) const {
+AI_FORCE_INLINE
+bool aiColor4t<TReal>::operator< (const aiColor4t<TReal>& other) const {
     return r < other.r || (
         r == other.r && (
             g < other.g || (
@@ -136,14 +165,17 @@ AI_FORCE_INLINE bool aiColor4t<TReal>::operator< (const aiColor4t<TReal>& other)
         )
     );
 }
+
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE aiColor4t<TReal> operator + (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator + (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
     return aiColor4t<TReal>( v1.r + v2.r, v1.g + v2.g, v1.b + v2.b, v1.a + v2.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE aiColor4t<TReal> operator - (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator - (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
     return aiColor4t<TReal>( v1.r - v2.r, v1.g - v2.g, v1.b - v2.b, v1.a - v2.a);
 }
 // ------------------------------------------------------------------------------------------------
@@ -153,53 +185,63 @@ AI_FORCE_INLINE aiColor4t<TReal> operator * (const aiColor4t<TReal>& v1, const a
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE aiColor4t<TReal> operator / (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator / (const aiColor4t<TReal>& v1, const aiColor4t<TReal>& v2)    {
     return aiColor4t<TReal>( v1.r / v2.r, v1.g / v2.g, v1.b / v2.b, v1.a / v2.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE aiColor4t<TReal> operator * ( TReal f, const aiColor4t<TReal>& v)   {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator * ( TReal f, const aiColor4t<TReal>& v)   {
     return aiColor4t<TReal>( f*v.r, f*v.g, f*v.b, f*v.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator * ( const aiColor4t<TReal>& v, TReal f)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator * ( const aiColor4t<TReal>& v, TReal f)  {
     return aiColor4t<TReal>( f*v.r, f*v.g, f*v.b, f*v.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator / ( const aiColor4t<TReal>& v, TReal f)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator / ( const aiColor4t<TReal>& v, TReal f)  {
     return v * (1/f);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator / ( TReal f,const aiColor4t<TReal>& v)   {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator / ( TReal f,const aiColor4t<TReal>& v)   {
     return aiColor4t<TReal>(f,f,f,f)/v;
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator + ( const aiColor4t<TReal>& v, TReal f)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator + ( const aiColor4t<TReal>& v, TReal f)  {
     return aiColor4t<TReal>( f+v.r, f+v.g, f+v.b, f+v.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator - ( const aiColor4t<TReal>& v, TReal f)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator - ( const aiColor4t<TReal>& v, TReal f)  {
     return aiColor4t<TReal>( v.r-f, v.g-f, v.b-f, v.a-f);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator + ( TReal f, const aiColor4t<TReal>& v)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator + ( TReal f, const aiColor4t<TReal>& v)  {
     return aiColor4t<TReal>( f+v.r, f+v.g, f+v.b, f+v.a);
 }
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-AI_FORCE_INLINE  aiColor4t<TReal> operator - ( TReal f, const aiColor4t<TReal>& v)  {
+AI_FORCE_INLINE
+aiColor4t<TReal> operator - ( TReal f, const aiColor4t<TReal>& v)  {
     return aiColor4t<TReal>( f-v.r, f-v.g, f-v.b, f-v.a);
 }
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiColor4t<TReal> :: IsBlack() const {
+AI_FORCE_INLINE
+bool aiColor4t<TReal>::IsBlack() const {
     // The alpha component doesn't care here. black is black.
     static const TReal epsilon = 10e-3f;
     return std::fabs( r ) < epsilon && std::fabs( g ) < epsilon && std::fabs( b ) < epsilon;
diff --git a/include/assimp/defs.h b/include/assimp/defs.h
index 05a5e3fd4..71579a5c7 100644
--- a/include/assimp/defs.h
+++ b/include/assimp/defs.h
@@ -5,8 +5,6 @@ Open Asset Import Library (assimp)
 
 Copyright (c) 2006-2019, assimp team
 
-
-
 All rights reserved.
 
 Redistribution and use of this software in source and binary forms,
@@ -50,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_DEFINES_H_INC
 #define AI_DEFINES_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/config.h>
 
 //////////////////////////////////////////////////////////////////////////
@@ -291,9 +293,10 @@ static const ai_real ai_epsilon = (ai_real) 0.00001;
 #endif
 
 
-/* To avoid running out of memory
- * This can be adjusted for specific use cases
- * It's NOT a total limit, just a limit for individual allocations
+/**
+ *  To avoid running out of memory
+ *  This can be adjusted for specific use cases
+ *  It's NOT a total limit, just a limit for individual allocations
  */
 #define AI_MAX_ALLOC(type) ((256U * 1024 * 1024) / sizeof(type))
 
@@ -307,4 +310,13 @@ static const ai_real ai_epsilon = (ai_real) 0.00001;
 #  endif
 #endif // _MSC_VER
 
+/**
+ *  Helper macro to set a pointer to NULL in debug builds
+ */
+#if (defined ASSIMP_BUILD_DEBUG)
+#   define AI_DEBUG_INVALIDATE_PTR(x) x = NULL;
+#else
+#   define AI_DEBUG_INVALIDATE_PTR(x)
+#endif
+
 #endif // !! AI_DEFINES_H_INC
diff --git a/include/assimp/fast_atof.h b/include/assimp/fast_atof.h
index 62ea969e9..6e9a1bba7 100644
--- a/include/assimp/fast_atof.h
+++ b/include/assimp/fast_atof.h
@@ -13,10 +13,14 @@
 //     to ensure long numbers are handled correctly
 // ------------------------------------------------------------------------------------
 
-
+#pragma once
 #ifndef FAST_A_TO_F_H_INCLUDED
 #define FAST_A_TO_F_H_INCLUDED
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <cmath>
 #include <limits>
 #include <stdint.h>
diff --git a/include/assimp/importerdesc.h b/include/assimp/importerdesc.h
index 36e387f01..0a6919c1a 100644
--- a/include/assimp/importerdesc.h
+++ b/include/assimp/importerdesc.h
@@ -48,11 +48,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_IMPORTER_DESC_H_INC
 #define AI_IMPORTER_DESC_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 
 /** Mixed set of flags for #aiImporterDesc, indicating some features
   *  common to many importers*/
-enum aiImporterFlags
-{
+enum aiImporterFlags {
     /** Indicates that there is a textual encoding of the
      *  file format; and that it is supported.*/
     aiImporterFlags_SupportTextFlavour = 0x1,
@@ -87,8 +90,7 @@ enum aiImporterFlags
  *  as importers/exporters are added to Assimp, so it might be useful
  *  to have a common mechanism to query some rough importer
  *  characteristics. */
-struct aiImporterDesc
-{
+struct aiImporterDesc {
     /** Full name of the importer (i.e. Blender3D importer)*/
     const char* mName;
 
diff --git a/include/assimp/light.h b/include/assimp/light.h
index 1667cfb8c..bdb2368c4 100644
--- a/include/assimp/light.h
+++ b/include/assimp/light.h
@@ -49,7 +49,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_LIGHT_H_INC
 #define AI_LIGHT_H_INC
 
-#include "types.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/types.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/assimp/material.h b/include/assimp/material.h
index 206eb2a2b..19a7c6970 100644
--- a/include/assimp/material.h
+++ b/include/assimp/material.h
@@ -48,7 +48,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MATERIAL_H_INC
 #define AI_MATERIAL_H_INC
 
-#include "types.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/types.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/assimp/material.inl b/include/assimp/material.inl
index b05d6af6c..8ae6b88d3 100644
--- a/include/assimp/material.inl
+++ b/include/assimp/material.inl
@@ -49,14 +49,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MATERIAL_INL_INC
 #define AI_MATERIAL_INL_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 // ---------------------------------------------------------------------------
-inline aiPropertyTypeInfo ai_real_to_property_type_info(float)
-{
+AI_FORCE_INLINE
+aiPropertyTypeInfo ai_real_to_property_type_info(float) {
 	return aiPTI_Float;
 }
 
-inline aiPropertyTypeInfo ai_real_to_property_type_info(double)
-{
+AI_FORCE_INLINE
+aiPropertyTypeInfo ai_real_to_property_type_info(double) {
 	return aiPTI_Double;
 }
 // ---------------------------------------------------------------------------
@@ -64,30 +68,30 @@ inline aiPropertyTypeInfo ai_real_to_property_type_info(double)
 //! @cond never
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::GetTexture( aiTextureType type,
-   unsigned int  index,
-   C_STRUCT aiString* path,
-   aiTextureMapping* mapping    /*= NULL*/,
-   unsigned int* uvindex        /*= NULL*/,
-   ai_real* blend               /*= NULL*/,
-   aiTextureOp* op              /*= NULL*/,
-   aiTextureMapMode* mapmode    /*= NULL*/) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::GetTexture( aiTextureType type,
+       unsigned int  index,
+       C_STRUCT aiString* path,
+       aiTextureMapping* mapping    /*= NULL*/,
+       unsigned int* uvindex        /*= NULL*/,
+       ai_real* blend               /*= NULL*/,
+       aiTextureOp* op              /*= NULL*/,
+       aiTextureMapMode* mapmode    /*= NULL*/) const {
     return ::aiGetMaterialTexture(this,type,index,path,mapping,uvindex,blend,op,mapmode);
 }
 
 // ---------------------------------------------------------------------------
-inline unsigned int aiMaterial::GetTextureCount(aiTextureType type) const
-{
+AI_FORCE_INLINE
+unsigned int aiMaterial::GetTextureCount(aiTextureType type) const {
     return ::aiGetMaterialTextureCount(this,type);
 }
 
 // ---------------------------------------------------------------------------
 template <typename Type>
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx, Type* pOut,
-    unsigned int* pMax) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx, Type* pOut,
+        unsigned int* pMax) const {
     unsigned int iNum = pMax ? *pMax : 1;
 
     const aiMaterialProperty* prop;
@@ -114,9 +118,9 @@ inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
 
 // ---------------------------------------------------------------------------
 template <typename Type>
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,Type& pOut) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,Type& pOut) const {
     const aiMaterialProperty* prop;
     const aiReturn ret = ::aiGetMaterialProperty(this,pKey,type,idx,
         (const aiMaterialProperty**)&prop);
@@ -136,60 +140,56 @@ inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,ai_real* pOut,
-    unsigned int* pMax) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,ai_real* pOut,
+        unsigned int* pMax) const {
     return ::aiGetMaterialFloatArray(this,pKey,type,idx,pOut,pMax);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,int* pOut,
-    unsigned int* pMax) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,int* pOut,
+        unsigned int* pMax) const {
     return ::aiGetMaterialIntegerArray(this,pKey,type,idx,pOut,pMax);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,ai_real& pOut) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,ai_real& pOut) const {
     return aiGetMaterialFloat(this,pKey,type,idx,&pOut);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,int& pOut) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,int& pOut) const {
     return aiGetMaterialInteger(this,pKey,type,idx,&pOut);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,aiColor4D& pOut) const
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,aiColor4D& pOut) const {
     return aiGetMaterialColor(this,pKey,type,idx,&pOut);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,aiColor3D& pOut) const
-{
+AI_FORCE_INLINE aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,aiColor3D& pOut) const {
     aiColor4D c;
     const aiReturn ret = aiGetMaterialColor(this,pKey,type,idx,&c);
     pOut = aiColor3D(c.r,c.g,c.b);
     return ret;
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,aiString& pOut) const
-{
+AI_FORCE_INLINE aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,aiString& pOut) const {
     return aiGetMaterialString(this,pKey,type,idx,&pOut);
 }
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
-    unsigned int idx,aiUVTransform& pOut) const
-{
+AI_FORCE_INLINE aiReturn aiMaterial::Get(const char* pKey,unsigned int type,
+        unsigned int idx,aiUVTransform& pOut) const {
     return aiGetMaterialUVTransform(this,pKey,type,idx,&pOut);
 }
 
-
 // ---------------------------------------------------------------------------
 template<class TYPE>
 aiReturn aiMaterial::AddProperty (const TYPE* pInput,
@@ -204,84 +204,83 @@ aiReturn aiMaterial::AddProperty (const TYPE* pInput,
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const float* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE aiReturn aiMaterial::AddProperty(const float* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(float),
         pKey,type,index,aiPTI_Float);
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const double* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const double* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(double),
         pKey,type,index,aiPTI_Double);
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const aiUVTransform* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const aiUVTransform* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiUVTransform),
         pKey,type,index,ai_real_to_property_type_info(pInput->mRotation));
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const aiColor4D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const aiColor4D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiColor4D),
         pKey,type,index,ai_real_to_property_type_info(pInput->a));
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const aiColor3D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const aiColor3D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiColor3D),
         pKey,type,index,ai_real_to_property_type_info(pInput->b));
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const aiVector3D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const aiVector3D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiVector3D),
         pKey,type,index,ai_real_to_property_type_info(pInput->x));
 }
 
 // ---------------------------------------------------------------------------
-inline aiReturn aiMaterial::AddProperty(const int* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty(const int* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(int),
         pKey,type,index,aiPTI_Integer);
@@ -296,12 +295,12 @@ inline aiReturn aiMaterial::AddProperty(const int* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<float>(const float* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<float>(const float* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(float),
         pKey,type,index,aiPTI_Float);
@@ -309,12 +308,12 @@ inline aiReturn aiMaterial::AddProperty<float>(const float* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<double>(const double* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<double>(const double* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(double),
         pKey,type,index,aiPTI_Double);
@@ -322,12 +321,12 @@ inline aiReturn aiMaterial::AddProperty<double>(const double* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<aiUVTransform>(const aiUVTransform* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<aiUVTransform>(const aiUVTransform* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiUVTransform),
         pKey,type,index,aiPTI_Float);
@@ -335,12 +334,12 @@ inline aiReturn aiMaterial::AddProperty<aiUVTransform>(const aiUVTransform* pInp
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<aiColor4D>(const aiColor4D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<aiColor4D>(const aiColor4D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiColor4D),
         pKey,type,index,aiPTI_Float);
@@ -348,12 +347,12 @@ inline aiReturn aiMaterial::AddProperty<aiColor4D>(const aiColor4D* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<aiColor3D>(const aiColor3D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<aiColor3D>(const aiColor3D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiColor3D),
         pKey,type,index,aiPTI_Float);
@@ -361,12 +360,12 @@ inline aiReturn aiMaterial::AddProperty<aiColor3D>(const aiColor3D* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<aiVector3D>(const aiVector3D* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<aiVector3D>(const aiVector3D* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(aiVector3D),
         pKey,type,index,aiPTI_Float);
@@ -374,12 +373,12 @@ inline aiReturn aiMaterial::AddProperty<aiVector3D>(const aiVector3D* pInput,
 
 // ---------------------------------------------------------------------------
 template<>
-inline aiReturn aiMaterial::AddProperty<int>(const int* pInput,
-    const unsigned int pNumValues,
-    const char* pKey,
-    unsigned int type,
-    unsigned int index)
-{
+AI_FORCE_INLINE
+aiReturn aiMaterial::AddProperty<int>(const int* pInput,
+        const unsigned int pNumValues,
+        const char* pKey,
+        unsigned int type,
+        unsigned int index) {
     return AddBinaryProperty((const void*)pInput,
         pNumValues * sizeof(int),
         pKey,type,index,aiPTI_Integer);
diff --git a/include/assimp/matrix3x3.h b/include/assimp/matrix3x3.h
index 22b69561f..2c26cf92b 100644
--- a/include/assimp/matrix3x3.h
+++ b/include/assimp/matrix3x3.h
@@ -48,7 +48,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MATRIX3X3_H_INC
 #define AI_MATRIX3X3_H_INC
 
-#include "defs.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/defs.h>
 
 #ifdef __cplusplus
 
@@ -65,10 +69,8 @@ template <typename T> class aiVector2t;
  *  defined thereby.
  */
 template <typename TReal>
-class aiMatrix3x3t
-{
+class aiMatrix3x3t {
 public:
-
     aiMatrix3x3t() AI_NO_EXCEPT :
         a1(static_cast<TReal>(1.0f)), a2(), a3(),
         b1(), b2(static_cast<TReal>(1.0f)), b3(),
@@ -82,8 +84,6 @@ public:
         c1(_c1), c2(_c2), c3(_c3)
     {}
 
-public:
-
     // matrix multiplication.
     aiMatrix3x3t& operator *= (const aiMatrix3x3t& m);
     aiMatrix3x3t  operator  * (const aiMatrix3x3t& m) const;
@@ -101,8 +101,6 @@ public:
     template <typename TOther>
     operator aiMatrix3x3t<TOther> () const;
 
-public:
-
     // -------------------------------------------------------------------
     /** @brief Construction from a 4x4 matrix. The remaining parts
      *  of the matrix are ignored.
@@ -122,7 +120,6 @@ public:
     aiMatrix3x3t& Inverse();
     TReal Determinant() const;
 
-public:
     // -------------------------------------------------------------------
     /** @brief Returns a rotation matrix for a rotation around z
      *  @param a Rotation angle, in radians
diff --git a/include/assimp/matrix3x3.inl b/include/assimp/matrix3x3.inl
index d9d45a3e9..1ce8c9691 100644
--- a/include/assimp/matrix3x3.inl
+++ b/include/assimp/matrix3x3.inl
@@ -48,10 +48,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MATRIX3X3_INL_INC
 #define AI_MATRIX3X3_INL_INC
 
-#ifdef __cplusplus
-#include "matrix3x3.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+#include <assimp/matrix3x3.h>
+#include <assimp/matrix4x4.h>
 
-#include "matrix4x4.h"
 #include <algorithm>
 #include <cmath>
 #include <limits>
@@ -59,8 +63,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // ------------------------------------------------------------------------------------------------
 // Construction from a 4x4 matrix. The remaining parts of the matrix are ignored.
 template <typename TReal>
-inline aiMatrix3x3t<TReal>::aiMatrix3x3t( const aiMatrix4x4t<TReal>& pMatrix)
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>::aiMatrix3x3t( const aiMatrix4x4t<TReal>& pMatrix) {
     a1 = pMatrix.a1; a2 = pMatrix.a2; a3 = pMatrix.a3;
     b1 = pMatrix.b1; b2 = pMatrix.b2; b3 = pMatrix.b3;
     c1 = pMatrix.c1; c2 = pMatrix.c2; c3 = pMatrix.c3;
@@ -68,8 +72,8 @@ inline aiMatrix3x3t<TReal>::aiMatrix3x3t( const aiMatrix4x4t<TReal>& pMatrix)
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::operator *= (const aiMatrix3x3t<TReal>& m)
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::operator *= (const aiMatrix3x3t<TReal>& m) {
     *this = aiMatrix3x3t<TReal>(m.a1 * a1 + m.b1 * a2 + m.c1 * a3,
         m.a2 * a1 + m.b2 * a2 + m.c2 * a3,
         m.a3 * a1 + m.b3 * a2 + m.c3 * a3,
@@ -85,8 +89,7 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::operator *= (const aiMatrix3x3t
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
 template <typename TOther>
-aiMatrix3x3t<TReal>::operator aiMatrix3x3t<TOther> () const
-{
+aiMatrix3x3t<TReal>::operator aiMatrix3x3t<TOther> () const {
     return aiMatrix3x3t<TOther>(static_cast<TOther>(a1),static_cast<TOther>(a2),static_cast<TOther>(a3),
         static_cast<TOther>(b1),static_cast<TOther>(b2),static_cast<TOther>(b3),
         static_cast<TOther>(c1),static_cast<TOther>(c2),static_cast<TOther>(c3));
@@ -94,8 +97,8 @@ aiMatrix3x3t<TReal>::operator aiMatrix3x3t<TOther> () const
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal> aiMatrix3x3t<TReal>::operator* (const aiMatrix3x3t<TReal>& m) const
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal> aiMatrix3x3t<TReal>::operator* (const aiMatrix3x3t<TReal>& m) const {
     aiMatrix3x3t<TReal> temp( *this);
     temp *= m;
     return temp;
@@ -103,7 +106,8 @@ inline aiMatrix3x3t<TReal> aiMatrix3x3t<TReal>::operator* (const aiMatrix3x3t<TR
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) {
+AI_FORCE_INLINE
+TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) {
     switch ( p_iIndex ) {
         case 0:
             return &a1;
@@ -119,7 +123,8 @@ inline TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) {
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline const TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) const {
+AI_FORCE_INLINE
+const TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) const {
     switch ( p_iIndex ) {
         case 0:
             return &a1;
@@ -135,8 +140,8 @@ inline const TReal* aiMatrix3x3t<TReal>::operator[] (unsigned int p_iIndex) cons
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiMatrix3x3t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+bool aiMatrix3x3t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const {
     return a1 == m.a1 && a2 == m.a2 && a3 == m.a3 &&
            b1 == m.b1 && b2 == m.b2 && b3 == m.b3 &&
            c1 == m.c1 && c2 == m.c2 && c3 == m.c3;
@@ -144,14 +149,15 @@ inline bool aiMatrix3x3t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiMatrix3x3t<TReal>::operator!= (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+bool aiMatrix3x3t<TReal>::operator!= (const aiMatrix4x4t<TReal>& m) const {
     return !(*this == m);
 }
 
 // ---------------------------------------------------------------------------
 template<typename TReal>
-inline bool aiMatrix3x3t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsilon) const {
+AI_FORCE_INLINE
+bool aiMatrix3x3t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsilon) const {
     return
         std::abs(a1 - m.a1) <= epsilon &&
         std::abs(a2 - m.a2) <= epsilon &&
@@ -166,8 +172,8 @@ inline bool aiMatrix3x3t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsil
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Transpose()
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Transpose() {
     // (TReal&) don't remove, GCC complains cause of packed fields
     std::swap( (TReal&)a2, (TReal&)b1);
     std::swap( (TReal&)a3, (TReal&)c1);
@@ -177,15 +183,15 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Transpose()
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline TReal aiMatrix3x3t<TReal>::Determinant() const
-{
+AI_FORCE_INLINE
+TReal aiMatrix3x3t<TReal>::Determinant() const {
     return a1*b2*c3 - a1*b3*c2 + a2*b3*c1 - a2*b1*c3 + a3*b1*c2 - a3*b2*c1;
 }
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Inverse()
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Inverse() {
     // Compute the reciprocal determinant
     TReal det = Determinant();
     if(det == static_cast<TReal>(0.0))
@@ -219,8 +225,8 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Inverse()
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::RotationZ(TReal a, aiMatrix3x3t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::RotationZ(TReal a, aiMatrix3x3t<TReal>& out) {
     out.a1 = out.b2 = std::cos(a);
     out.b1 = std::sin(a);
     out.a2 = - out.b1;
@@ -234,8 +240,8 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::RotationZ(TReal a, aiMatrix3x3t
 // ------------------------------------------------------------------------------------------------
 // Returns a rotation matrix for a rotation around an arbitrary axis.
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Rotation( TReal a, const aiVector3t<TReal>& axis, aiMatrix3x3t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Rotation( TReal a, const aiVector3t<TReal>& axis, aiMatrix3x3t<TReal>& out) {
   TReal c = std::cos( a), s = std::sin( a), t = 1 - c;
   TReal x = axis.x, y = axis.y, z = axis.z;
 
@@ -249,8 +255,8 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Rotation( TReal a, const aiVect
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Translation( const aiVector2t<TReal>& v, aiMatrix3x3t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Translation( const aiVector2t<TReal>& v, aiMatrix3x3t<TReal>& out) {
     out = aiMatrix3x3t<TReal>();
     out.a3 = v.x;
     out.b3 = v.y;
@@ -268,9 +274,8 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::Translation( const aiVector2t<T
  */
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::FromToMatrix(const aiVector3t<TReal>& from,
-    const aiVector3t<TReal>& to, aiMatrix3x3t<TReal>& mtx)
-{
+AI_FORCE_INLINE aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::FromToMatrix(const aiVector3t<TReal>& from,
+        const aiVector3t<TReal>& to, aiMatrix3x3t<TReal>& mtx) {
     const TReal e = from * to;
     const TReal f = (e < 0)? -e:e;
 
@@ -352,6 +357,5 @@ inline aiMatrix3x3t<TReal>& aiMatrix3x3t<TReal>::FromToMatrix(const aiVector3t<T
     return mtx;
 }
 
-
 #endif // __cplusplus
 #endif // AI_MATRIX3X3_INL_INC
diff --git a/include/assimp/matrix4x4.h b/include/assimp/matrix4x4.h
index 046bb535f..8fc216f66 100644
--- a/include/assimp/matrix4x4.h
+++ b/include/assimp/matrix4x4.h
@@ -47,8 +47,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MATRIX4X4_H_INC
 #define AI_MATRIX4X4_H_INC
 
-#include "vector3.h"
-#include "defs.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/vector3.h>
+#include <assimp/defs.h>
 
 #ifdef __cplusplus
 
@@ -66,8 +70,7 @@ template<typename TReal> class aiQuaterniont;
  *  defined thereby.
  */
 template<typename TReal>
-class aiMatrix4x4t
-{
+class aiMatrix4x4t {
 public:
 
     /** set to identity */
@@ -91,8 +94,6 @@ public:
     aiMatrix4x4t(const aiVector3t<TReal>& scaling, const aiQuaterniont<TReal>& rotation,
         const aiVector3t<TReal>& position);
 
-public:
-
     // array access operators
 	/** @fn TReal* operator[] (unsigned int p_iIndex)
 	 *  @param [in] p_iIndex - index of the row.
@@ -120,8 +121,6 @@ public:
     template <typename TOther>
     operator aiMatrix4x4t<TOther> () const;
 
-public:
-
     // -------------------------------------------------------------------
     /** @brief Transpose the matrix */
     aiMatrix4x4t& Transpose();
@@ -182,7 +181,6 @@ public:
     void DecomposeNoScaling (aiQuaterniont<TReal>& rotation,
         aiVector3t<TReal>& position) const;
 
-
     // -------------------------------------------------------------------
     /** @brief Creates a trafo matrix from a set of euler angles
      *  @param x Rotation angle for the x-axis, in radians
@@ -192,7 +190,6 @@ public:
     aiMatrix4x4t& FromEulerAnglesXYZ(TReal x, TReal y, TReal z);
     aiMatrix4x4t& FromEulerAnglesXYZ(const aiVector3t<TReal>& blubb);
 
-public:
     // -------------------------------------------------------------------
     /** @brief Returns a rotation matrix for a rotation around the x axis
      *  @param a Rotation angle, in radians
@@ -256,7 +253,6 @@ public:
     static aiMatrix4x4t& FromToMatrix(const aiVector3t<TReal>& from,
             const aiVector3t<TReal>& to, aiMatrix4x4t& out);
 
-public:
     TReal a1, a2, a3, a4;
     TReal b1, b2, b3, b4;
     TReal c1, c2, c3, c4;
diff --git a/include/assimp/matrix4x4.inl b/include/assimp/matrix4x4.inl
index 19e684917..84079974f 100644
--- a/include/assimp/matrix4x4.inl
+++ b/include/assimp/matrix4x4.inl
@@ -60,12 +60,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
 aiMatrix4x4t<TReal>::aiMatrix4x4t() AI_NO_EXCEPT :
-    a1(1.0f), a2(), a3(), a4(),
-    b1(), b2(1.0f), b3(), b4(),
-    c1(), c2(), c3(1.0f), c4(),
-    d1(), d2(), d3(), d4(1.0f)
-{
-
+        a1(1.0f), a2(), a3(), a4(),
+        b1(), b2(1.0f), b3(), b4(),
+        c1(), c2(), c3(1.0f), c4(),
+        d1(), d2(), d3(), d4(1.0f) {
+    // empty
 }
 
 // ----------------------------------------------------------------------------------------
@@ -74,19 +73,17 @@ aiMatrix4x4t<TReal>::aiMatrix4x4t (TReal _a1, TReal _a2, TReal _a3, TReal _a4,
               TReal _b1, TReal _b2, TReal _b3, TReal _b4,
               TReal _c1, TReal _c2, TReal _c3, TReal _c4,
               TReal _d1, TReal _d2, TReal _d3, TReal _d4) :
-    a1(_a1), a2(_a2), a3(_a3), a4(_a4),
-    b1(_b1), b2(_b2), b3(_b3), b4(_b4),
-    c1(_c1), c2(_c2), c3(_c3), c4(_c4),
-    d1(_d1), d2(_d2), d3(_d3), d4(_d4)
-{
-
+        a1(_a1), a2(_a2), a3(_a3), a4(_a4),
+        b1(_b1), b2(_b2), b3(_b3), b4(_b4),
+        c1(_c1), c2(_c2), c3(_c3), c4(_c4),
+        d1(_d1), d2(_d2), d3(_d3), d4(_d4) {
+    // empty
 }
 
 // ------------------------------------------------------------------------------------------------
 template <typename TReal>
 template <typename TOther>
-aiMatrix4x4t<TReal>::operator aiMatrix4x4t<TOther> () const
-{
+aiMatrix4x4t<TReal>::operator aiMatrix4x4t<TOther> () const {
     return aiMatrix4x4t<TOther>(static_cast<TOther>(a1),static_cast<TOther>(a2),static_cast<TOther>(a3),static_cast<TOther>(a4),
         static_cast<TOther>(b1),static_cast<TOther>(b2),static_cast<TOther>(b3),static_cast<TOther>(b4),
         static_cast<TOther>(c1),static_cast<TOther>(c2),static_cast<TOther>(c3),static_cast<TOther>(c4),
@@ -96,8 +93,8 @@ aiMatrix4x4t<TReal>::operator aiMatrix4x4t<TOther> () const
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiMatrix3x3t<TReal>& m)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiMatrix3x3t<TReal>& m) {
     a1 = m.a1; a2 = m.a2; a3 = m.a3; a4 = static_cast<TReal>(0.0);
     b1 = m.b1; b2 = m.b2; b3 = m.b3; b4 = static_cast<TReal>(0.0);
     c1 = m.c1; c2 = m.c2; c3 = m.c3; c4 = static_cast<TReal>(0.0);
@@ -106,8 +103,8 @@ inline aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiMatrix3x3t<TReal>& m)
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiVector3t<TReal>& scaling, const aiQuaterniont<TReal>& rotation, const aiVector3t<TReal>& position)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiVector3t<TReal>& scaling, const aiQuaterniont<TReal>& rotation, const aiVector3t<TReal>& position) {
     // build a 3x3 rotation matrix
     aiMatrix3x3t<TReal> m = rotation.GetMatrix();
 
@@ -134,8 +131,8 @@ inline aiMatrix4x4t<TReal>::aiMatrix4x4t (const aiVector3t<TReal>& scaling, cons
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::operator *= (const aiMatrix4x4t<TReal>& m)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::operator *= (const aiMatrix4x4t<TReal>& m) {
     *this = aiMatrix4x4t<TReal>(
         m.a1 * a1 + m.b1 * a2 + m.c1 * a3 + m.d1 * a4,
         m.a2 * a1 + m.b2 * a2 + m.c2 * a3 + m.d2 * a4,
@@ -158,8 +155,7 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::operator *= (const aiMatrix4x4t
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator* (const TReal& aFloat) const
-{
+AI_FORCE_INLINE aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator* (const TReal& aFloat) const {
     aiMatrix4x4t<TReal> temp(
         a1 * aFloat,
         a2 * aFloat,
@@ -182,8 +178,8 @@ inline aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator* (const TReal& aFloat)
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator+ (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator+ (const aiMatrix4x4t<TReal>& m) const {
     aiMatrix4x4t<TReal> temp(
         m.a1 + a1,
         m.a2 + a2,
@@ -206,18 +202,16 @@ inline aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator+ (const aiMatrix4x4t<TR
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator* (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal> aiMatrix4x4t<TReal>::operator* (const aiMatrix4x4t<TReal>& m) const {
     aiMatrix4x4t<TReal> temp( *this);
     temp *= m;
     return temp;
 }
 
-
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Transpose()
-{
+AI_FORCE_INLINE aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Transpose() {
     // (TReal&) don't remove, GCC complains cause of packed fields
     std::swap( (TReal&)b1, (TReal&)a2);
     std::swap( (TReal&)c1, (TReal&)a3);
@@ -228,11 +222,10 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Transpose()
     return *this;
 }
 
-
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline TReal aiMatrix4x4t<TReal>::Determinant() const
-{
+AI_FORCE_INLINE
+TReal aiMatrix4x4t<TReal>::Determinant() const {
     return a1*b2*c3*d4 - a1*b2*c4*d3 + a1*b3*c4*d2 - a1*b3*c2*d4
         + a1*b4*c2*d3 - a1*b4*c3*d2 - a2*b3*c4*d1 + a2*b3*c1*d4
         - a2*b4*c1*d3 + a2*b4*c3*d1 - a2*b1*c3*d4 + a2*b1*c4*d3
@@ -243,8 +236,8 @@ inline TReal aiMatrix4x4t<TReal>::Determinant() const
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Inverse()
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Inverse() {
     // Compute the reciprocal determinant
     const TReal det = Determinant();
     if(det == static_cast<TReal>(0.0))
@@ -288,9 +281,10 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Inverse()
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) {
+AI_FORCE_INLINE
+TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) {
     if (p_iIndex > 3) {
-        return NULL;
+        return nullptr;
     }
     switch ( p_iIndex ) {
         case 0:
@@ -309,9 +303,10 @@ inline TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) {
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline const TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) const {
+AI_FORCE_INLINE
+const TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) const {
     if (p_iIndex > 3) {
-        return NULL;
+        return nullptr;
     }
 
     switch ( p_iIndex ) {
@@ -331,8 +326,8 @@ inline const TReal* aiMatrix4x4t<TReal>::operator[](unsigned int p_iIndex) const
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiMatrix4x4t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+bool aiMatrix4x4t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const {
     return (a1 == m.a1 && a2 == m.a2 && a3 == m.a3 && a4 == m.a4 &&
             b1 == m.b1 && b2 == m.b2 && b3 == m.b3 && b4 == m.b4 &&
             c1 == m.c1 && c2 == m.c2 && c3 == m.c3 && c4 == m.c4 &&
@@ -341,14 +336,15 @@ inline bool aiMatrix4x4t<TReal>::operator== (const aiMatrix4x4t<TReal>& m) const
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiMatrix4x4t<TReal>::operator!= (const aiMatrix4x4t<TReal>& m) const
-{
+AI_FORCE_INLINE
+bool aiMatrix4x4t<TReal>::operator!= (const aiMatrix4x4t<TReal>& m) const {
     return !(*this == m);
 }
 
 // ---------------------------------------------------------------------------
 template<typename TReal>
-inline bool aiMatrix4x4t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsilon) const {
+AI_FORCE_INLINE
+bool aiMatrix4x4t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsilon) const {
     return
         std::abs(a1 - m.a1) <= epsilon &&
         std::abs(a2 - m.a2) <= epsilon &&
@@ -400,13 +396,10 @@ inline bool aiMatrix4x4t<TReal>::Equal(const aiMatrix4x4t<TReal>& m, TReal epsil
 	\
 	do {} while(false)
 
-
-
-
 template <typename TReal>
-inline void aiMatrix4x4t<TReal>::Decompose (aiVector3t<TReal>& pScaling, aiQuaterniont<TReal>& pRotation,
-    aiVector3t<TReal>& pPosition) const
-{
+AI_FORCE_INLINE
+void aiMatrix4x4t<TReal>::Decompose (aiVector3t<TReal>& pScaling, aiQuaterniont<TReal>& pRotation,
+        aiVector3t<TReal>& pPosition) const {
 	ASSIMP_MATRIX4_4_DECOMPOSE_PART;
 
     // build a 3x3 rotation matrix
@@ -419,7 +412,7 @@ inline void aiMatrix4x4t<TReal>::Decompose (aiVector3t<TReal>& pScaling, aiQuate
 }
 
 template <typename TReal>
-inline
+AI_FORCE_INLINE
 void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TReal>& pRotation, aiVector3t<TReal>& pPosition) const {
 	ASSIMP_MATRIX4_4_DECOMPOSE_PART;
 
@@ -474,10 +467,10 @@ void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TRea
 #undef ASSIMP_MATRIX4_4_DECOMPOSE_PART
 
 template <typename TReal>
-inline void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TReal>& pRotationAxis, TReal& pRotationAngle,
-											aiVector3t<TReal>& pPosition) const
-{
-aiQuaterniont<TReal> pRotation;
+AI_FORCE_INLINE
+void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TReal>& pRotationAxis, TReal& pRotationAngle,
+											aiVector3t<TReal>& pPosition) const {
+    aiQuaterniont<TReal> pRotation;
 
 	Decompose(pScaling, pRotation, pPosition);
 	pRotation.Normalize();
@@ -499,9 +492,9 @@ aiQuaterniont<TReal> pRotation;
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline void aiMatrix4x4t<TReal>::DecomposeNoScaling (aiQuaterniont<TReal>& rotation,
-    aiVector3t<TReal>& position) const
-{
+AI_FORCE_INLINE
+void aiMatrix4x4t<TReal>::DecomposeNoScaling (aiQuaterniont<TReal>& rotation,
+        aiVector3t<TReal>& position) const {
     const aiMatrix4x4t<TReal>& _this = *this;
 
     // extract translation
@@ -515,15 +508,15 @@ inline void aiMatrix4x4t<TReal>::DecomposeNoScaling (aiQuaterniont<TReal>& rotat
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromEulerAnglesXYZ(const aiVector3t<TReal>& blubb)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromEulerAnglesXYZ(const aiVector3t<TReal>& blubb) {
     return FromEulerAnglesXYZ(blubb.x,blubb.y,blubb.z);
 }
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromEulerAnglesXYZ(TReal x, TReal y, TReal z)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromEulerAnglesXYZ(TReal x, TReal y, TReal z) {
     aiMatrix4x4t<TReal>& _this = *this;
 
     TReal cx = std::cos(x);
@@ -551,8 +544,8 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromEulerAnglesXYZ(TReal x, TRe
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline bool aiMatrix4x4t<TReal>::IsIdentity() const
-{
+AI_FORCE_INLINE
+bool aiMatrix4x4t<TReal>::IsIdentity() const {
     // Use a small epsilon to solve floating-point inaccuracies
     const static TReal epsilon = 10e-3f;
 
@@ -576,8 +569,8 @@ inline bool aiMatrix4x4t<TReal>::IsIdentity() const
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationX(TReal a, aiMatrix4x4t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationX(TReal a, aiMatrix4x4t<TReal>& out) {
     /*
          |  1  0       0       0 |
      M = |  0  cos(A) -sin(A)  0 |
@@ -591,8 +584,8 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationX(TReal a, aiMatrix4x4t
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationY(TReal a, aiMatrix4x4t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationY(TReal a, aiMatrix4x4t<TReal>& out) {
     /*
          |  cos(A)  0   sin(A)  0 |
      M = |  0       1   0       0 |
@@ -607,8 +600,8 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationY(TReal a, aiMatrix4x4t
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationZ(TReal a, aiMatrix4x4t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationZ(TReal a, aiMatrix4x4t<TReal>& out) {
     /*
          |  cos(A)  -sin(A)   0   0 |
      M = |  sin(A)   cos(A)   0   0 |
@@ -623,26 +616,25 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::RotationZ(TReal a, aiMatrix4x4t
 // ----------------------------------------------------------------------------------------
 // Returns a rotation matrix for a rotation around an arbitrary axis.
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Rotation( TReal a, const aiVector3t<TReal>& axis, aiMatrix4x4t<TReal>& out)
-{
-  TReal c = std::cos( a), s = std::sin( a), t = 1 - c;
-  TReal x = axis.x, y = axis.y, z = axis.z;
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Rotation( TReal a, const aiVector3t<TReal>& axis, aiMatrix4x4t<TReal>& out) {
+    TReal c = std::cos( a), s = std::sin( a), t = 1 - c;
+    TReal x = axis.x, y = axis.y, z = axis.z;
 
-  // Many thanks to MathWorld and Wikipedia
-  out.a1 = t*x*x + c;   out.a2 = t*x*y - s*z; out.a3 = t*x*z + s*y;
-  out.b1 = t*x*y + s*z; out.b2 = t*y*y + c;   out.b3 = t*y*z - s*x;
-  out.c1 = t*x*z - s*y; out.c2 = t*y*z + s*x; out.c3 = t*z*z + c;
-  out.a4 = out.b4 = out.c4 = static_cast<TReal>(0.0);
-  out.d1 = out.d2 = out.d3 = static_cast<TReal>(0.0);
-  out.d4 = static_cast<TReal>(1.0);
+    // Many thanks to MathWorld and Wikipedia
+    out.a1 = t*x*x + c;   out.a2 = t*x*y - s*z; out.a3 = t*x*z + s*y;
+    out.b1 = t*x*y + s*z; out.b2 = t*y*y + c;   out.b3 = t*y*z - s*x;
+    out.c1 = t*x*z - s*y; out.c2 = t*y*z + s*x; out.c3 = t*z*z + c;
+    out.a4 = out.b4 = out.c4 = static_cast<TReal>(0.0);
+    out.d1 = out.d2 = out.d3 = static_cast<TReal>(0.0);
+    out.d4 = static_cast<TReal>(1.0);
 
-  return out;
+    return out;
 }
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Translation( const aiVector3t<TReal>& v, aiMatrix4x4t<TReal>& out)
-{
+AI_FORCE_INLINE aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Translation( const aiVector3t<TReal>& v, aiMatrix4x4t<TReal>& out) {
     out = aiMatrix4x4t<TReal>();
     out.a4 = v.x;
     out.b4 = v.y;
@@ -652,8 +644,8 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Translation( const aiVector3t<T
 
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Scaling( const aiVector3t<TReal>& v, aiMatrix4x4t<TReal>& out)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Scaling( const aiVector3t<TReal>& v, aiMatrix4x4t<TReal>& out) {
     out = aiMatrix4x4t<TReal>();
     out.a1 = v.x;
     out.b2 = v.y;
@@ -672,9 +664,9 @@ inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::Scaling( const aiVector3t<TReal
  */
 // ----------------------------------------------------------------------------------------
 template <typename TReal>
-inline aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromToMatrix(const aiVector3t<TReal>& from,
-    const aiVector3t<TReal>& to, aiMatrix4x4t<TReal>& mtx)
-{
+AI_FORCE_INLINE
+aiMatrix4x4t<TReal>& aiMatrix4x4t<TReal>::FromToMatrix(const aiVector3t<TReal>& from,
+        const aiVector3t<TReal>& to, aiMatrix4x4t<TReal>& mtx) {
     aiMatrix3x3t<TReal> m3;
     aiMatrix3x3t<TReal>::FromToMatrix(from,to,m3);
     mtx = aiMatrix4x4t<TReal>(m3);
diff --git a/include/assimp/mesh.h b/include/assimp/mesh.h
index f1628f1f5..eb30ad5df 100644
--- a/include/assimp/mesh.h
+++ b/include/assimp/mesh.h
@@ -48,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_MESH_H_INC
 #define AI_MESH_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/types.h>
 #include <assimp/aabb.h>
 
diff --git a/include/assimp/metadata.h b/include/assimp/metadata.h
index 3a1dd1442..849d90f48 100644
--- a/include/assimp/metadata.h
+++ b/include/assimp/metadata.h
@@ -48,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_METADATA_H_INC
 #define AI_METADATA_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #if defined(_MSC_VER) && (_MSC_VER <= 1500)
 #  include "Compiler/pstdint.h"
 #else
diff --git a/include/assimp/pbrmaterial.h b/include/assimp/pbrmaterial.h
index ce5f82217..892a6347f 100644
--- a/include/assimp/pbrmaterial.h
+++ b/include/assimp/pbrmaterial.h
@@ -5,8 +5,6 @@ Open Asset Import Library (assimp)
 
 Copyright (c) 2006-2019, assimp team
 
-
-
 All rights reserved.
 
 Redistribution and use of this software in source and binary forms,
@@ -44,9 +42,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** @file pbrmaterial.h
  *  @brief Defines the material system of the library
  */
+#pragma once
 #ifndef AI_PBRMATERIAL_H_INC
 #define AI_PBRMATERIAL_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #define AI_MATKEY_GLTF_PBRMETALLICROUGHNESS_BASE_COLOR_FACTOR "$mat.gltf.pbrMetallicRoughness.baseColorFactor", 0, 0
 #define AI_MATKEY_GLTF_PBRMETALLICROUGHNESS_METALLIC_FACTOR "$mat.gltf.pbrMetallicRoughness.metallicFactor", 0, 0
 #define AI_MATKEY_GLTF_PBRMETALLICROUGHNESS_ROUGHNESS_FACTOR "$mat.gltf.pbrMetallicRoughness.roughnessFactor", 0, 0
diff --git a/include/assimp/postprocess.h b/include/assimp/postprocess.h
index 2a7441421..77d387c7e 100644
--- a/include/assimp/postprocess.h
+++ b/include/assimp/postprocess.h
@@ -47,7 +47,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_POSTPROCESS_H_INC
 #define AI_POSTPROCESS_H_INC
 
-#include "types.h"
+#include <assimp/types.h>
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/assimp/qnan.h b/include/assimp/qnan.h
index 0918bde5e..06780da5b 100644
--- a/include/assimp/qnan.h
+++ b/include/assimp/qnan.h
@@ -50,19 +50,23 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *     but last time I checked compiler coverage was so bad that I decided
  *     to reinvent the wheel.
  */
-
+#pragma once
 #ifndef AI_QNAN_H_INCLUDED
 #define AI_QNAN_H_INCLUDED
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #include <assimp/defs.h>
+
 #include <limits>
 #include <stdint.h>
 
 // ---------------------------------------------------------------------------
 /** Data structure to represent the bit pattern of a 32 Bit
  *         IEEE 754 floating-point number. */
-union _IEEESingle
-{
+union _IEEESingle {
     float Float;
     struct
     {
@@ -75,8 +79,7 @@ union _IEEESingle
 // ---------------------------------------------------------------------------
 /** Data structure to represent the bit pattern of a 64 Bit
  *         IEEE 754 floating-point number. */
-union _IEEEDouble
-{
+union _IEEEDouble {
     double Double;
     struct
     {
@@ -89,8 +92,7 @@ union _IEEEDouble
 // ---------------------------------------------------------------------------
 /** Check whether a given float is qNaN.
  *  @param in Input value */
-AI_FORCE_INLINE bool is_qnan(float in)
-{
+AI_FORCE_INLINE bool is_qnan(float in) {
     // the straightforward solution does not work:
     //   return (in != in);
     // compiler generates code like this
@@ -107,8 +109,7 @@ AI_FORCE_INLINE bool is_qnan(float in)
 // ---------------------------------------------------------------------------
 /** Check whether a given double is qNaN.
  *  @param in Input value */
-AI_FORCE_INLINE bool is_qnan(double in)
-{
+AI_FORCE_INLINE bool is_qnan(double in) {
     // the straightforward solution does not work:
     //   return (in != in);
     // compiler generates code like this
@@ -127,8 +128,7 @@ AI_FORCE_INLINE bool is_qnan(double in)
  *
  *  Denorms return false, they're treated like normal values.
  *  @param in Input value */
-AI_FORCE_INLINE bool is_special_float(float in)
-{
+AI_FORCE_INLINE bool is_special_float(float in) {
     _IEEESingle temp;
     memcpy(&temp, &in, sizeof(float));
     return (temp.IEEE.Exp == (1u << 8)-1);
@@ -139,8 +139,7 @@ AI_FORCE_INLINE bool is_special_float(float in)
  *
  *  Denorms return false, they're treated like normal values.
  *  @param in Input value */
-AI_FORCE_INLINE bool is_special_float(double in)
-{
+AI_FORCE_INLINE bool is_special_float(double in) {
    _IEEESingle temp;
     memcpy(&temp, &in, sizeof(float));
     return (temp.IEEE.Exp == (1u << 11)-1);
@@ -150,15 +149,13 @@ AI_FORCE_INLINE bool is_special_float(double in)
 /** Check whether a float is NOT qNaN.
  *  @param in Input value */
 template<class TReal>
-AI_FORCE_INLINE bool is_not_qnan(TReal in)
-{
+AI_FORCE_INLINE bool is_not_qnan(TReal in) {
     return !is_qnan(in);
 }
 
 // ---------------------------------------------------------------------------
 /** @brief Get a fresh qnan.  */
-AI_FORCE_INLINE ai_real get_qnan()
-{
+AI_FORCE_INLINE ai_real get_qnan() {
     return std::numeric_limits<ai_real>::quiet_NaN();
 }
 
diff --git a/include/assimp/quaternion.h b/include/assimp/quaternion.h
index 96574d24b..ae45959b4 100644
--- a/include/assimp/quaternion.h
+++ b/include/assimp/quaternion.h
@@ -49,7 +49,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifdef __cplusplus
 
-#include "defs.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/defs.h>
 
 template <typename TReal> class aiVector3t;
 template <typename TReal> class aiMatrix3x3t;
diff --git a/include/assimp/quaternion.inl b/include/assimp/quaternion.inl
index c26648215..3ce514d1b 100644
--- a/include/assimp/quaternion.inl
+++ b/include/assimp/quaternion.inl
@@ -48,8 +48,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_QUATERNION_INL_INC
 #define AI_QUATERNION_INL_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef __cplusplus
-#include "quaternion.h"
+#include <assimp/quaternion.h>
 
 #include <cmath>
 
diff --git a/include/assimp/scene.h b/include/assimp/scene.h
index 2667db85b..e69c81803 100644
--- a/include/assimp/scene.h
+++ b/include/assimp/scene.h
@@ -48,14 +48,18 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_SCENE_H_INC
 #define AI_SCENE_H_INC
 
-#include "types.h"
-#include "texture.h"
-#include "mesh.h"
-#include "light.h"
-#include "camera.h"
-#include "material.h"
-#include "anim.h"
-#include "metadata.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/types.h>
+#include <assimp/texture.h>
+#include <assimp/mesh.h>
+#include <assimp/light.h>
+#include <assimp/camera.h>
+#include <assimp/material.h>
+#include <assimp/anim.h>
+#include <assimp/metadata.h>
 
 #ifdef __cplusplus
 #  include <cstdlib>
diff --git a/include/assimp/texture.h b/include/assimp/texture.h
index dc6cbef65..0867659f4 100644
--- a/include/assimp/texture.h
+++ b/include/assimp/texture.h
@@ -5,8 +5,6 @@ Open Asset Import Library (assimp)
 
 Copyright (c) 2006-2019, assimp team
 
-
-
 All rights reserved.
 
 Redistribution and use of this software in source and binary forms,
@@ -53,13 +51,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_TEXTURE_H_INC
 #define AI_TEXTURE_H_INC
 
-#include "types.h"
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/types.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-
 // --------------------------------------------------------------------------------
 
 /** \def AI_EMBEDDED_TEXNAME_PREFIX
@@ -79,7 +80,6 @@ extern "C" {
 #   define AI_MAKE_EMBEDDED_TEXNAME(_n_) AI_EMBEDDED_TEXNAME_PREFIX # _n_
 #endif
 
-
 #include "./Compiler/pushpack1.h"
 
 // --------------------------------------------------------------------------------
@@ -87,8 +87,7 @@ extern "C" {
 *
 *  Used by aiTexture.
 */
-struct aiTexel
-{
+struct aiTexel {
     unsigned char b,g,r,a;
 
 #ifdef __cplusplus
diff --git a/include/assimp/types.h b/include/assimp/types.h
index 8ad5680f3..e32cae331 100644
--- a/include/assimp/types.h
+++ b/include/assimp/types.h
@@ -48,6 +48,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_TYPES_H_INC
 #define AI_TYPES_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 // Some runtime headers
 #include <sys/types.h>
 #include <stddef.h>
@@ -56,15 +60,15 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <stdint.h>
 
 // Our compile configuration
-#include "defs.h"
+#include <assimp/defs.h>
 
 // Some types moved to separate header due to size of operators
-#include "vector3.h"
-#include "vector2.h"
-#include "color4.h"
-#include "matrix3x3.h"
-#include "matrix4x4.h"
-#include "quaternion.h"
+#include <assimp/vector3.h>
+#include <assimp/vector2.h>
+#include <assimp/color4.h>
+#include <assimp/matrix3x3.h>
+#include <assimp/matrix4x4.h>
+#include <assimp/quaternion.h>
 
 typedef int32_t ai_int32;
 typedef uint32_t ai_uint32 ;
@@ -74,9 +78,8 @@ typedef uint32_t ai_uint32 ;
 #include <new>      // for std::nothrow_t
 #include <string>   // for aiString::Set(const std::string&)
 
-
 namespace Assimp    {
-    //! @cond never
+//! @cond never
 namespace Intern        {
     // --------------------------------------------------------------------
     /** @brief Internal helper class to utilize our internal new/delete
diff --git a/include/assimp/vector2.h b/include/assimp/vector2.h
index d5ef00154..c8b1ebbbc 100644
--- a/include/assimp/vector2.h
+++ b/include/assimp/vector2.h
@@ -47,6 +47,10 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_VECTOR2D_H_INC
 #define AI_VECTOR2D_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef __cplusplus
 #   include <cmath>
 #else
diff --git a/include/assimp/vector2.inl b/include/assimp/vector2.inl
index 3b7a7beab..4bbf432ff 100644
--- a/include/assimp/vector2.inl
+++ b/include/assimp/vector2.inl
@@ -48,8 +48,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_VECTOR2D_INL_INC
 #define AI_VECTOR2D_INL_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef __cplusplus
-#include "vector2.h"
+#include <assimp/vector2.h>
 
 #include <cmath>
 
diff --git a/include/assimp/vector3.h b/include/assimp/vector3.h
index 7ff25cf0a..fffeb12ad 100644
--- a/include/assimp/vector3.h
+++ b/include/assimp/vector3.h
@@ -47,13 +47,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_VECTOR3D_H_INC
 #define AI_VECTOR3D_H_INC
 
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
 #ifdef __cplusplus
 #   include <cmath>
 #else
 #   include <math.h>
 #endif
 
-#include "defs.h"
+#include <assimp/defs.h>
 
 #ifdef __cplusplus
 
@@ -63,16 +67,13 @@ template<typename TReal> class aiMatrix4x4t;
 // ---------------------------------------------------------------------------
 /** Represents a three-dimensional vector. */
 template <typename TReal>
-class aiVector3t
-{
+class aiVector3t {
 public:
     aiVector3t() AI_NO_EXCEPT : x(), y(), z() {}
     aiVector3t(TReal _x, TReal _y, TReal _z) : x(_x), y(_y), z(_z) {}
     explicit aiVector3t (TReal _xyz ) : x(_xyz), y(_xyz), z(_xyz) {}
     aiVector3t( const aiVector3t& o ) = default;
 
-public:
-
     // combined operators
     const aiVector3t& operator += (const aiVector3t& o);
     const aiVector3t& operator -= (const aiVector3t& o);
@@ -97,7 +98,6 @@ public:
     template <typename TOther>
     operator aiVector3t<TOther> () const;
 
-public:
     /** @brief Set the components of a vector
      *  @param pX X component
      *  @param pY Y component
diff --git a/include/assimp/vector3.inl b/include/assimp/vector3.inl
index 2fce6edde..6682d3b32 100644
--- a/include/assimp/vector3.inl
+++ b/include/assimp/vector3.inl
@@ -49,7 +49,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define AI_VECTOR3D_INL_INC
 
 #ifdef __cplusplus
-#include "vector3.h"
+#include <assimp/vector3.h>
 
 #include <cmath>
 
diff --git a/include/assimp/version.h b/include/assimp/version.h
index c62a40e11..2fdd37a43 100644
--- a/include/assimp/version.h
+++ b/include/assimp/version.h
@@ -49,7 +49,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_VERSION_H_INC
 #define AI_VERSION_H_INC
 
-#include "defs.h"
+#include <assimp/defs.h>
 
 #ifdef __cplusplus
 extern "C" {