SCons: Add CPPEXTPATH for external includes

modules/text_server_fb/text_server_fb.cpp

@@ -61,17 +61,11 @@ using namespace godot;
 // Thirdparty headers.
 
 #ifdef MODULE_MSDFGEN_ENABLED
-#ifdef _MSC_VER
-#pragma warning(disable : 4458)
-#endif
 #include <core/EdgeHolder.h>
 #include <core/ShapeDistanceFinder.h>
 #include <core/contour-combiners.h>
 #include <core/edge-selectors.h>
 #include <msdfgen.h>
-#ifdef _MSC_VER
-#pragma warning(default : 4458)
-#endif
 #endif
 
 #ifdef MODULE_FREETYPE_ENABLED