easily: moved out of config.h some definitions that we could do
dynamically per target architecture.
NOTE: ppc, m68k and sparc optimizations are currently missing and should
be imported from ffmpeg 0.5 before we can build avcodec plugin for these
targets. Hence why it's still X86_ONLY qualified.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30185 a95241bf-73f2-0310-859d-f6bbb57e9c96