Packages libx264 and ffmpeg are built with ASM options on x86 platforms.
The current libx264 version no longer builds with YASM and requires NASM.
ffmpeg 3.x can be built with either YASM or NASM however, furture 4.x versions
will require NASM.
Signed-off-by: Ted Hess <thess@kitschensync.net>
Acked-by: Rosen Penev <rosenp@gmail.com>
