Fix compiling stb texture tool on Windows

Source/Engine/Tools/TextureTool/TextureTool.stb.cpp

@@ -65,6 +65,8 @@
 
 #endif
 
+#undef MessageBox
+
 static void stbWrite(void* context, void* data, int size)
 {
     auto file = (FileWriteStream*)context;

Source/ThirdParty/detex/detex.h

@@ -72,7 +72,11 @@ __BEGIN_DECLS
 #include <stdint.h>
 #include <stdbool.h>
 
+#if defined(_MSC_VER)
+#define DETEX_INLINE_ONLY __forceinline
+#else
 #define DETEX_INLINE_ONLY __attribute__((always_inline)) inline
+#endif
 #define DETEX_RESTRICT __restrict
 
 /* Maximum uncompressed block size in bytes. */