diff --git a/code/AssetLib/M3D/M3DWrapper.cpp b/code/AssetLib/M3D/M3DWrapper.cpp
index 30452c776..05087d592 100644
--- a/code/AssetLib/M3D/M3DWrapper.cpp
+++ b/code/AssetLib/M3D/M3DWrapper.cpp
@@ -39,8 +39,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----------------------------------------------------------------------
 */
-#ifndef ASSIMP_BUILD_NO_M3D_IMPORTER
-#if !(ASSIMP_BUILD_NO_EXPORT || ASSIMP_BUILD_NO_M3D_EXPORTER)
+#if !defined ASSIMP_BUILD_NO_M3D_IMPORTER || !(defined ASSIMP_BUILD_NO_EXPORT || defined ASSIMP_BUILD_NO_M3D_EXPORTER)
 
 #include "M3DWrapper.h"
 
@@ -149,4 +148,3 @@ void M3DWrapper::ClearSave() {
 } // namespace Assimp
 
 #endif
-#endif
diff --git a/code/AssetLib/M3D/M3DWrapper.h b/code/AssetLib/M3D/M3DWrapper.h
index c75ff1027..880aca996 100644
--- a/code/AssetLib/M3D/M3DWrapper.h
+++ b/code/AssetLib/M3D/M3DWrapper.h
@@ -47,8 +47,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_M3DWRAPPER_H_INC
 #define AI_M3DWRAPPER_H_INC
 
-#ifndef ASSIMP_BUILD_NO_M3D_IMPORTER
-#if !(ASSIMP_BUILD_NO_EXPORT || ASSIMP_BUILD_NO_M3D_EXPORTER)  
+#if !defined ASSIMP_BUILD_NO_M3D_IMPORTER || !(defined ASSIMP_BUILD_NO_EXPORT || defined ASSIMP_BUILD_NO_M3D_EXPORTER)
 
 #include <memory>
 #include <vector>
@@ -126,7 +125,6 @@ inline m3d_t *M3DWrapper::M3D() const {
 
 } // namespace Assimp
 
-#endif
 #endif // ASSIMP_BUILD_NO_M3D_IMPORTER
 
 #endif // AI_M3DWRAPPER_H_INC