Using language compliant header guards.

include/bx/float4_sse.h

@@ -403,4 +403,4 @@ IMPLEMENT_TEST(xyzw , 0xf);
 #define float4_floor float4_floor_ni
 #include "float4_ni.h"
 
-#endif // __FLOAT4_SSE_H__
+#endif // BX_FLOAT4_SSE_H_HEADER_GUARD

include/bx/handlealloc.h

@@ -169,4 +169,4 @@ namespace bx
 
 } // namespace bx
 
-#endif // __HANDLE_ALLOC_H__
+#endif // BX_HANDLE_ALLOC_H_HEADER_GUARD

include/compat/mingw/alloca.h

@@ -1,6 +1,6 @@
-#ifndef __MINGW32__ALLOCA_H__
-#define __MINGW32__ALLOCA_H__
+#ifndef MINGW32_ALLOCA_H_HEADER_GUARD
+#define MINGW32_ALLOCA_H_HEADER_GUARD
 
 #include <malloc.h>
 
-#endif // __MINGW32__ALLOCA_H__
+#endif // MINGW32_ALLOCA_H_HEADER_GUARD