avcodec/utils: mark codec argument as const in ff_lock_avcodec()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/internal.h

@@ -167,7 +167,7 @@ int ff_init_buffer_info(AVCodecContext *s, AVFrame *frame);
 void avpriv_color_frame(AVFrame *frame, const int color[4]);
 
 extern volatile int ff_avcodec_locked;
-int ff_lock_avcodec(AVCodecContext *log_ctx, AVCodec *codec);
+int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec);
 int ff_unlock_avcodec(void);
 
 int avpriv_lock_avformat(void);

libavcodec/utils.c

@@ -3604,7 +3604,7 @@ int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op))
     return 0;
 }
 
-int ff_lock_avcodec(AVCodecContext *log_ctx, AVCodec *codec)
+int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec)
 {
     if (lockmgr_cb) {
         if ((*lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))