"Mac OS X/x86 won't build the MMX/YUV inline assembly without optimizations
 enabled (not enough registers), so for now, we only build it if we see
 the __OPTIMIZE__ #define, which GCC provides when you build at -O1 or higher."

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%402528