ffmpeg: libffmpeg-audio-dec and -custom use integrated opus decoder
For libffmpeg-audio-dec:
Remove @DEVEL flag from libffmpeg-audio-dec. Reasoning for this is
that choosing this package does not rquire any further action by the
builder in what codecs or formats should be built in.
libffmpeg-custom, the other libffmpeg to require @DEVEL, does need
further interaction.
Add @BUILD_PATENTED as at least one of the audio codecs is likely
patent protected.
Add ffmpeg's native Opus decoder to libffmpeg-audio-dec
Remove libopus dependency to libffmpeg-audio-dec as libopus provides
decode and encode support for Opus audio. Since FFmpeg can decode
Opus audio on its own, and libffmpeg-audio-dec is intended for audio
decoding, libopus is no longer required for Opus audio support.
For libffmpeg-custom:
Add in options for ffmpeg's integrated Opus decoder
Signed-off-by: Ian Leonard <antonlacon@gmail.com>