Give the libnut muxer a lib prefix in its name so it does not conflict with

the native implementation.

Originally committed as revision 10941 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/libnut.c

@@ -151,7 +151,7 @@ static int nut_write_trailer(AVFormatContext * avf) {
 }
 
 AVOutputFormat libnut_muxer = {
-    "nut",
+    "libnut",
     "nut format",
     "video/x-nut",
     "nut",