avformat/internal: Make AVFormatContext* a logctx in ff_get_extradata

I.e. use void* instead of AVFormatContext*, because it is only used
for logging.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/internal.h

@@ -659,7 +659,7 @@ int ff_alloc_extradata(AVCodecParameters *par, int size);
  * @param size size of extradata
  * @return >= 0 if OK, AVERROR_xxx on error
  */
-int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size);
+int ff_get_extradata(void *logctx, AVCodecParameters *par, AVIOContext *pb, int size);
 
 /**
  * Copies the whilelists from one context to the other

libavformat/utils.c

@@ -359,7 +359,7 @@ int ff_alloc_extradata(AVCodecParameters *par, int size)
     return 0;
 }
 
-int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size)
+int ff_get_extradata(void *logctx, AVCodecParameters *par, AVIOContext *pb, int size)
 {
     int ret = ff_alloc_extradata(par, size);
     if (ret < 0)
@@ -368,7 +368,7 @@ int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb
     if (ret < 0) {
         av_freep(&par->extradata);
         par->extradata_size = 0;
-        av_log(s, AV_LOG_ERROR, "Failed to read extradata of size %d\n", size);
+        av_log(logctx, AV_LOG_ERROR, "Failed to read extradata of size %d\n", size);
         return ret;
     }