Add parameter names to av_log/av_vlog function declarations.

Doxygen gets confused without an explicit parameter name.

Originally committed as revision 23972 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/log.h

@@ -123,12 +123,12 @@ typedef struct {
  * @see av_vlog
  */
 #ifdef __GNUC__
-void av_log(void*, int level, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 3, 4)));
+void av_log(void *avcl, int level, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 3, 4)));
 #else
-void av_log(void*, int level, const char *fmt, ...);
+void av_log(void *avcl, int level, const char *fmt, ...);
 #endif
 
-void av_vlog(void*, int level, const char *fmt, va_list);
+void av_vlog(void *avcl, int level, const char *fmt, va_list);
 int av_log_get_level(void);
 void av_log_set_level(int);
 void av_log_set_callback(void (*)(void*, int, const char*, va_list));