Use auto for AVCodec
The geniuses over at FFmpeg decided to constify this API, so old
versions of the library will return AVCodec *, while new versions
of the libary will return const AVCodec *, which, in C++, are not
OK to convert between.
Rather than use some macro hell in ffmscompat.h, we can work around
this by using auto.
configure: Remove deprecated API use
all: Update AVPacket API usage
AVPackets must all be on the heap now, since it is no longer
part of the libav* ABI.
Commits: