avcodec: on audio encode, sync timestamps more often from input

Ref #9022
avcodec: map AV_NOPTS_VALUE and VLC_TS_INVALID
httplive: small simplification
avcodec: remove AV_NOPTS_VALUE cast

AV_NOPTS_VALUE already contains a cast to int64_t
Revert "contrib: vpx: update to 1.2.0"

This reverts commit 7e2edc0d901a4ffe1fc429a81cccdb69dc186372.

http://webm.googlecode.com/files/libvpx-v1.1.0.tar.bz2
 is a release tarball
http://webm.googlecode.com/files/libvpx-v1.2.0.tar.bz2
 is a daily updated git snapshot

libvpx has no release tarballs (or releases) anymore apparently.
theora: fix memleak in case of error or discontinuity

Closes #9414
macosx: fix behaviour of mute menu items (close #9685)
auhal: do not change volume when muted
macosx: also use toggleMute for apple-script action

The previous code does not make sense as there is no unmute action.
skins2: add support for subtitle drag'n'drop

This patch copies the Qt interface implementation wrt file dropping, namely:
- first try it as a subtitle file if it is relevant
- second, try it as an item to be added to the playlist if not a subtitle
contrib: speex: fix build with recent automake

Disable the API function returning version string as it uses old
automake functionality that might be buggy/not supported anymore.
Don't bother fixing properly as we don't use that function and libspeex is now
an abandoned projet (move to Opus!)
avformat: set bits per pixel for video codecs

Fix decoding of MSRLE samples with avformat demuxer
avcodec: transmit palette to libavcodec >= 54
avcommon: Move the libavutil check where it belongs

Unbreak avformat-only builds.

Signed-off-by: Rafaël Carré <funman@videolan.org>
Provide extradata also if the video is not palettized. All samples in tickets #4017, #5952 and #9546 plays nicely.

Signed-off-by: Rafaël Carré <funman@videolan.org>
Win32 threads: remove functions forbidden on Windows Store

Do not create a suspended thread so ResumeThread becomes unnecessary.
Busy loop over thread handle if by misfortune the thread ends before
_beginthreadex has returned.

Do not use SetThreadPriority on Windows Store.

Set the cancelled thread bit outside of the APC procedure.
APC is still used to wake up the cancelled thread when it is in an alertable state
(SleepEx or WaitForMultipleObjectsEx).
Since QueueUserAPC is forbidden on Windows Store we check the cancelled state every
50 ms.
avcodec: missed AV_NOPTS_VALUE check
Add HEVC support in MKV
Temporarily fix build until a better way is found
GLSpectrum: fix memory leak (cid #1100858)