Add AVClass for the private context, this will be used for codec specific options.

Originally committed as revision 25250 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -2762,6 +2762,7 @@ typedef struct AVCodec {
     const enum SampleFormat *sample_fmts;   ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
     const int64_t *channel_layouts;         ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
     uint8_t max_lowres;                     ///< maximum value for lowres supported by the decoder
+    AVClass *priv_class;                    ///< AVClass for the private context
 } AVCodec;
 
 /**