Use system memset/memcpy on Mac OS X, since Apple hand-tunes these for each

 processor they ship (and thus, it's likely to beat our code on PowerPC and
 Intel and whatever variants or new archs show up later).

--HG--
branch : SDL-1.2
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/branches/SDL-1.2%402323

include/SDL_stdinc.h

@@ -234,7 +234,10 @@ extern DECLSPEC void SDLCALL SDL_qsort(void *base, size_t nmemb, size_t size,
 extern DECLSPEC void * SDLCALL SDL_memset(void *dst, int c, size_t len);
 #endif
 
-#if defined(__GNUC__) && defined(i386)
+/* We can count on memset existing on Mac OS X and being well-tuned. */
+#if defined(__MACH__) && defined(__APPLE__)
+#define SDL_memset4(dst, val, len) memset(dst, val, (len)*4)
+#elif defined(__GNUC__) && defined(i386)
 #define SDL_memset4(dst, val, len)				\
 do {								\
 	int u0, u1, u2;						\
@@ -263,7 +266,10 @@ do {						\
 } while(0)
 #endif
 
-#if defined(__GNUC__) && defined(i386)
+/* We can count on memcpy existing on Mac OS X and being well-tuned. */
+#if defined(__MACH__) && defined(__APPLE__)
+#define SDL_memcpy(dst, src, len) memcpy(dst, src, len)
+#elif defined(__GNUC__) && defined(i386)
 #define SDL_memcpy(dst, src, len)					  \
 do {									  \
 	int u0, u1, u2;						  	  \
@@ -292,7 +298,10 @@ extern DECLSPEC void * SDLCALL SDL_memcpy(void *dst, const void *src, size_t len
 #endif
 #endif
 
-#if defined(__GNUC__) && defined(i386)
+/* We can count on memcpy existing on Mac OS X and being well-tuned. */
+#if defined(__MACH__) && defined(__APPLE__)
+#define SDL_memcpy4(dst, src, len) memcpy(dst, src, (len)*4)
+#elif defined(__GNUC__) && defined(i386)
 #define SDL_memcpy4(dst, src, len)				\
 do {								\
 	int ecx, edi, esi;					\