Fix SDL include in physfs in Xcode land

git-svn-id: http://svn.net-core.org/repos/t-engine4@608 51575b47-30f0-44d4-a5cc-537603b46e54

src/physfs/physfsrwops.h

@@ -24,7 +24,11 @@
 #define _INCLUDE_PHYSFSRWOPS_H_
 
 #include "physfs.h"
+#ifdef __APPLE__
+#include <SDL/SDL.h>
+#else
 #include "SDL.h"
+#endif
 
 #ifdef __cplusplus
 extern "C" {