Only define AltiVec vector syntax macro when AltiVec is enabled.

patch by Peter Ross, pross xvid org

Originally committed as revision 14073 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/internal.h

@@ -50,11 +50,13 @@
 #endif
 #endif
 
+#ifdef HAVE_ALTIVEC
 #ifdef HAVE_ALTIVEC_VECTOR_BRACES
 #define AVV(x...) {x}
 #else
 #define AVV(x...) (x)
 #endif
+#endif
 
 #ifndef M_PI
 #define M_PI    3.14159265358979323846