GXF muxer is no longer GPLed.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9632 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -757,7 +757,6 @@ audio_demuxer_deps_any="audio_oss audio_beos"
 audio_muxer_deps_any="audio_oss audio_beos"
 dc1394_demuxer_deps="dc1394"
 dv1394_demuxer_deps="dv1394"
-gxf_muxer_deps="gpl"
 libnut_demuxer_deps="libnut"
 libnut_muxer_deps="libnut"
 mp3_demuxer_deps="mpegaudio_parser"