Use FFmpeg-specific CPU feature definitions.

taken from a patch by Ronald S. Bultje, rbultje ronald.bitfreak net
Date: Thu, 07 Jun 2007 08:57:46 -0400
Subject: Re: [FFmpeg-devel] [PATCH] Coremake support - ffmpeg_nommx.patch (1/1)
 - ffmpeg-nommx.patch (1/1) - ff-cputest-noavconfig.patch (1/1)

Originally committed as revision 9250 to svn://svn.ffmpeg.org/ffmpeg/trunk