Move list_fmts() from ffmpeg.c to cmdutils.{h,c}, so that it can be

shared by the other ff* tools code.

Originally committed as revision 20812 to svn://svn.ffmpeg.org/ffmpeg/trunk

cmdutils.h

@@ -131,6 +131,8 @@ void set_context_opts(void *ctx, void *opts_ctx, int flags);
 
 void print_error(const char *filename, int err);
 
+void list_fmts(void (*get_fmt_string)(char *buf, int buf_size, int fmt), int nb_fmts);
+
 /**
  * Prints the program banner to stderr. The banner contents depend on the
  * current version of the repository and of the libav* libraries used by