Replace SYS_DARWIN by the more correct __APPLE_CC__, these preprocessor

directives are aimed at idiosyncracies of Apple's gcc version.

Originally committed as revision 10206 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ppc/dsputil_altivec.h

@@ -44,7 +44,7 @@ void avg_pixels16_altivec(uint8_t *block, const uint8_t *pixels, int line_size,
 #define WORD_s2 0x18,0x19,0x1a,0x1b
 #define WORD_s3 0x1c,0x1d,0x1e,0x1f
 
-#ifdef SYS_DARWIN
+#ifdef __APPLE_CC__
 #define vcprm(a,b,c,d) (const vector unsigned char)(WORD_ ## a, WORD_ ## b, WORD_ ## c, WORD_ ## d)
 #else
 #define vcprm(a,b,c,d) (const vector unsigned char){WORD_ ## a, WORD_ ## b, WORD_ ## c, WORD_ ## d}

libavcodec/ppc/mpegvideo_altivec.c

@@ -66,7 +66,7 @@ do { \
 }
 
 
-#ifdef SYS_DARWIN
+#ifdef __APPLE_CC__
 #define FOUROF(a) (a)
 #else
 // slower, for dumb non-apple GCC