We don't support this anymore.
This tries to exit in a controlled way after command line options are
applied in order to honor logging options and, in case of libmpv, not to
kill the host. Not sure if it would be better to just vomit text to
stderr and call abort().
This is pretty nasty, because FFmpeg/Libav is yet another library with a
global message callback. We do something with mutexes trying to get it
done, but of course we can't actually solve this problem. If more than
one library in a process use FFmpeg/Libav, only one of them will get log
messages.
Always pass around mp_log contexts in the option parser code. This of
course affects all users of this API as well.
In stream.c, pass a mp_null_log, because we can't do it properly yet.
This will be fixed later.
