SetClassLongPtr isn't available in MinGW yet

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401461

src/video/wincommon/SDL_syswm.c

@@ -220,6 +220,9 @@ void WIN_SetWMIcon(_THIS, SDL_Surface *icon, Uint8 *mask)
 	if ( screen_icn == NULL ) {
 		SDL_SetError("Couldn't create Win32 icon handle");
 	} else {
+#ifndef SetClassLongPtr
+#define SetClassLongPtr	SetClassLong
+#endif
 		SetClassLongPtr(SDL_Window, GCL_HICON, (LONG_PTR)screen_icn);
 	}
 	SDL_stack_free(icon_win32);