register nut muxer if libnut is used

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@6978 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/allformats.c

@@ -249,7 +249,9 @@ void av_register_all(void)
     av_register_input_format(&nut_demuxer);
 #endif
 #ifdef CONFIG_NUT_MUXER
-//    av_register_output_format(&nut_muxer);
+#ifdef CONFIG_LIBNUT
+    av_register_output_format(&nut_muxer);
+#endif
 #endif
 #ifdef CONFIG_NUV_DEMUXER
     av_register_input_format(&nuv_demuxer);