Add init and uninit functions to cmdutils, reduces code duplication

between ffmpeg and ffplay and avoids a valgrind error by freeing
avformat_opts->key.

Originally committed as revision 25309 to svn://svn.ffmpeg.org/ffmpeg/trunk

cmdutils.h

@@ -44,6 +44,17 @@ extern AVCodecContext *avcodec_opts[AVMEDIA_TYPE_NB];
 extern AVFormatContext *avformat_opts;
 extern struct SwsContext *sws_opts;
 
+/**
+ * Initialize the cmdutils option system, in particular
+ * allocate the *_opts contexts.
+ */
+void init_opts(void);
+/**
+ * Uninitialize the cmdutils option system, in particular
+ * free the *_opts contexts and their contents.
+ */
+void uninit_opts(void);
+
 /**
  * Trivial log callback.
  * Only suitable for show_help and similar since it lacks prefix handling.