avformat: add svag demuxer

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/allformats.c

@@ -294,6 +294,7 @@ void av_register_all(void)
     REGISTER_DEMUXER (SUBVIEWER1,       subviewer1);
     REGISTER_DEMUXER (SUBVIEWER,        subviewer);
     REGISTER_DEMUXER (SUP,              sup);
+    REGISTER_DEMUXER (SVAG,             svag);
     REGISTER_MUXDEMUX(SWF,              swf);
     REGISTER_DEMUXER (TAK,              tak);
     REGISTER_MUXER   (TEE,              tee);