Add mfspr-based AltiVec detection code. Currently not enabled in FFmpeg, because it crashes if the OS does not emulate mfspr.
Add mfspr-based AltiVec detection code.
Currently not enabled in FFmpeg, because it crashes if the OS does not
emulate mfspr.


git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@11569 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg