Bug#803839: compile time check

1) The patch as it stands is completely invalid. Each change needs to have a version / feature check for backwards compatibility. 2) The change in mkv_decoder.c is not done like that. The correct way is to #define either av_free_packet or av_destruct_packet in libavhelper.h . Again a #ifdef is need

Bug#803839: compile time check

Is there a compile time check for this version (e.g. LIBAVCODEC_VERSION_MAJOR) or even #ifdef AV_PIX_FMT_RGB24 ?