lavf/gifdec: fix typo

Signed-off-by: Paul B Mahol <onemda@gmail.com>
lavf/gifdec: cosmetics: remove extra whitespace

Signed-off-by: Paul B Mahol <onemda@gmail.com>
lavc/gif: remove some obsolete/irrelevant chunks

Some code was copy pasted from muxer, which still
have same comments but unlike encoder they are still
relevant to muxer.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
ffmpeg: add -guess_layout_max option.
lavfi: support unknown channel layouts.
lavfi: implement ff_all_channel_counts().
lavfi: implement ff_query_formats_all().
lavfi/sink_buffer: accept unknown channel layouts.

Add a field to the AVBufferSinkParams for a list of accepted
channel counts.
Change the default value for the lists in AVBufferSinkParams
to NULL, to let lavfi fill them with something useful.
The fail_enomem path is unneeded because filters are uninited
on failure.
lavfi/buffersrc: accept unknown channel layouts.
lavfi/af_aformat: accept unknown channel layouts.
lavfi/af_aresample: accept unknown channel layouts.
lavfi/af_anull: accept unknown channel layouts.
ffmpeg: support filtering of unknown channel layouts.
lavfi: version bump and change log entries after the last commits.
fate: add an attachment to the Matroska test.
lavfi/vf_drawtext: default to expansion=normal.
lavc/iff: ilbm: unbreak decoding on big endian

Fixes #2192.

Signed-off-by: Paul B Mahol <onemda@gmail.com>