diff --git a/code/AssetLib/STL/STLLoader.cpp b/code/AssetLib/STL/STLLoader.cpp
index 2087af850..cea448de1 100644
--- a/code/AssetLib/STL/STLLoader.cpp
+++ b/code/AssetLib/STL/STLLoader.cpp
@@ -73,7 +73,7 @@ static const aiImporterDesc desc = {
 // 1) 80 byte header
 // 2) 4 byte face count
 // 3) 50 bytes per face
-static bool IsBinarySTL(const char *buffer, unsigned int fileSize) {
+static bool IsBinarySTL(const char *buffer, size_t fileSize) {
     if (fileSize < 84) {
         return false;
     }
@@ -92,7 +92,7 @@ static const char UnicodeBoundary = 127;
 // An ascii STL buffer will begin with "solid NAME", where NAME is optional.
 // Note: The "solid NAME" check is necessary, but not sufficient, to determine
 // if the buffer is ASCII; a binary header could also begin with "solid NAME".
-static bool IsAsciiSTL(const char *buffer, unsigned int fileSize) {
+static bool IsAsciiSTL(const char *buffer, size_t fileSize) {
     if (IsBinarySTL(buffer, fileSize))
         return false;
 
@@ -172,7 +172,7 @@ void STLImporter::InternReadFile(const std::string &pFile, aiScene *pScene, IOSy
         throw DeadlyImportError("Failed to open STL file ", pFile, ".");
     }
 
-    mFileSize = (unsigned int)file->FileSize();
+    mFileSize = file->FileSize();
 
     // allocate storage and copy the contents of the file to a memory buffer
     // (terminate it with zero)
@@ -233,7 +233,7 @@ void STLImporter::LoadASCIIFile(aiNode *root) {
 
     // try to guess how many vertices we could have
     // assume we'll need 160 bytes for each face
-    size_t sizeEstimate = std::max(1u, mFileSize / 160u) * 3;
+    size_t sizeEstimate = std::max(1ull, mFileSize / 160ull) * 3ull;
     positionBuffer.reserve(sizeEstimate);
     normalBuffer.reserve(sizeEstimate);
 
@@ -284,8 +284,6 @@ void STLImporter::LoadASCIIFile(aiNode *root) {
                     ASSIMP_LOG_WARN("STL: A new facet begins but the old is not yet complete");
                 }
                 faceVertexCounter = 0;
-                normalBuffer.push_back(aiVector3D());
-                aiVector3D *vn = &normalBuffer.back();
 
                 sz += 6;
                 SkipSpaces(&sz);
@@ -295,15 +293,17 @@ void STLImporter::LoadASCIIFile(aiNode *root) {
                     if (sz[6] == '\0') {
                         throw DeadlyImportError("STL: unexpected EOF while parsing facet");
                     }
+                    aiVector3D vn;
                     sz += 7;
                     SkipSpaces(&sz);
-                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn->x);
+                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn.x);
                     SkipSpaces(&sz);
-                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn->y);
+                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn.y);
                     SkipSpaces(&sz);
-                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn->z);
-                    normalBuffer.push_back(*vn);
-                    normalBuffer.push_back(*vn);
+                    sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn.z);
+                    normalBuffer.emplace_back(vn);
+                    normalBuffer.emplace_back(vn);
+                    normalBuffer.emplace_back(vn);
                 }
             } else if (!strncmp(sz, "vertex", 6) && ::IsSpaceOrNewLine(*(sz + 6))) { // vertex 1.50000 1.50000 0.00000
                 if (faceVertexCounter >= 3) {
@@ -315,7 +315,7 @@ void STLImporter::LoadASCIIFile(aiNode *root) {
                     }
                     sz += 7;
                     SkipSpaces(&sz);
-                    positionBuffer.push_back(aiVector3D());
+                    positionBuffer.emplace_back();
                     aiVector3D *vn = &positionBuffer.back();
                     sz = fast_atoreal_move<ai_real>(sz, (ai_real &)vn->x);
                     SkipSpaces(&sz);
@@ -439,7 +439,7 @@ bool STLImporter::LoadBinaryFile() {
     pMesh->mNumFaces = *((uint32_t *)sz);
     sz += 4;
 
-    if (mFileSize < 84 + pMesh->mNumFaces * 50) {
+    if (mFileSize < 84ull + pMesh->mNumFaces * 50ull) {
         throw DeadlyImportError("STL: file is too small to hold all facets");
     }
 
diff --git a/code/AssetLib/STL/STLLoader.h b/code/AssetLib/STL/STLLoader.h
index a340abe6b..0be6a95f0 100644
--- a/code/AssetLib/STL/STLLoader.h
+++ b/code/AssetLib/STL/STLLoader.h
@@ -109,7 +109,7 @@ protected:
     const char* mBuffer;
 
     /** Size of the file, in bytes */
-    unsigned int mFileSize;
+    size_t mFileSize;
 
     /** Output scene */
     aiScene* mScene;
diff --git a/code/Common/ZipArchiveIOSystem.cpp b/code/Common/ZipArchiveIOSystem.cpp
index e0c9883d2..a29380838 100644
--- a/code/Common/ZipArchiveIOSystem.cpp
+++ b/code/Common/ZipArchiveIOSystem.cpp
@@ -196,7 +196,9 @@ zlib_filefunc_def IOSystem2Unzip::get(IOSystem *pIOHandler) {
     zlib_filefunc_def mapping;
 
     mapping.zopen_file = (open_file_func)open;
+#ifdef _UNZ_H
     mapping.zopendisk_file = (opendisk_file_func)opendisk;
+#endif
     mapping.zread_file = (read_file_func)read;
     mapping.zwrite_file = (write_file_func)write;
     mapping.ztell_file = (tell_file_func)tell;