This option is only used by mpegvideoenc, x264, xavs, and vpx.
It is a very codec-specific option, so deprecate the global variant.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

The -{vas}<option> syntax is now obsolete and deprecated, and has never
been documented or encouraged.

This allows us to test the slice threading code.

This reverts commit ce378f0d.

Snow is a toy codec with no real-world use and horrible code.

This makes the vsynth tests run only if the required codecs and
formats are enabled.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Signed-off-by: Janne Grunau <janne-libav@jannau.net>

GNU make 3.81 applies pattern rules in declaration order rather than
by stem length as in 3.82.  This moves the more generic patterns above
the more specific ones such that they work with either make version.
Some of the vsynth patterns are also simplified a little.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Signed-off-by: Mans Rullgard <mans@mansr.com>