vf_aspect: support variables in evaluating the aspect ratios

Example: -vf setsar=sar="sar*9/10"

Signed-off-by: Rudolf Polzer <divverent@xonotic.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
vf_scale: make the dar variable return the DAR.

Before, it just returned width/height. Correct is width/height*sar.

That way it is consistent with DAR as in probe output and setdar.

Signed-off-by: Rudolf Polzer <divverent@xonotic.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
attributes: disable flatten on llvm/clang
wtv: fix variable sign in format
ansi: fix possible use of uninitialized variables
Merge commit '34a0ac41a880039c7fb4b3abce10d8e2ce48fac7'

* commit '34a0ac41a880039c7fb4b3abce10d8e2ce48fac7':
  vf_aspect: support variables in evaluating the aspect ratios

Conflicts:
	Changelog
	doc/filters.texi
	libavfilter/vf_aspect.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '3a14b160bd442794c6a16a6a883adb547550e847'

* commit '3a14b160bd442794c6a16a6a883adb547550e847':
  vf_scale: make the dar variable return the DAR.

Conflicts:
	Changelog
	doc/filters.texi
	libavfilter/version.h

See: 61d55fda2b513caf18e37b27aba680a87840904a
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '5858a67f135a7395c548482c73cf3d39bcdd3022'

* commit '5858a67f135a7395c548482c73cf3d39bcdd3022':
  attributes: disable flatten on llvm/clang

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'c0bba95c2363641d3297b3852b2ece1474cda295'

* commit 'c0bba95c2363641d3297b3852b2ece1474cda295':
  wtv: fix variable sign in format

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '3ea5f64ffff0a51f62922efd2e2bc231b13b2179'

* commit '3ea5f64ffff0a51f62922efd2e2bc231b13b2179':
  ansi: fix possible use of uninitialized variables

Conflicts:
	libavcodec/ansi.c

Only partially merged, ffmpeg is not affected by this.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/ansi: set w/h correctly at the top

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>