configure: add config_exif for ffmpeg

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36427 b3059339-0415-0410-9bf9-f77b7e298cf2
Avoid reinitializing VDPAU on e.g. simple aspect changes.

This avoids decode error if frames from before the
aspect change are used as reference frames after.
It also reduces the issues when using VDPAU together
with -lavdopts threads=n


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36428 b3059339-0415-0410-9bf9-f77b7e298cf2