Add compiler switgxh for using static linkage for std_image

code/Common/Assimp.cpp

@@ -1284,7 +1284,9 @@ ASSIMP_API void aiQuaternionInterpolate(
 #if ASSIMP_NEEDS_STB_IMAGE
     // Share stb_image's PNG loader with other importers/exporters instead of bringing our own copy.
 #   define STBI_ONLY_PNG
+#   ifdef ASSIMP_USE_STB_IMAGE_STATIC
 #       define STB_IMAGE_STATIC
+#   endif
 #   define STB_IMAGE_IMPLEMENTATION
 #   include "Common/StbCommon.h"
 #endif

code/Pbrt/PbrtExporter.cpp

@@ -83,9 +83,7 @@ Other:
 #include <sstream>
 #include <string>
 
-#if ASSIMP_NEEDS_STB_IMAGE
 #include "Common/StbCommon.h"
-#endif
 
 using namespace Assimp;
 

test/unit/Main.cpp

@@ -1,6 +1,5 @@
 #include "../../include/assimp/DefaultLogger.hpp"
 #include "UnitTestPCH.h"
-
 #include <math.h>
 #include <time.h>