Fixes an assert in file from trac ticket 3188.

Fixes crash/valgrind errors in trac ticket 3188 and hang in 3274.

Runtime of the full 32x32 idct goes from 2446 to 2441 cycles (intra) or
from 1425 to 1306 cycles (inter). Overall runtime is not significantly
affected.

Runtime of all IDCTs together goes from 3327 to 2473 cycles (intra, i.e.
~35% faster) or from 2312 to 1448 cycles (inter, i.e. ~60% faster). Total
decode time of ped1080p.webm goes from 8.086sec to 7.974sec (1.4% faster).

Sub-IDCTs will follow later. ped1080.webm goes from 9.295s to 8.191s
(13.5% faster). The IDCT itself goes from 4372 (intra) or 4337 (inter)
to 403 (intra) or 329 (inter) cycles for the DC-only form, 23755 (intra)
or 23723 (inter) to 3497 (intra) or 3607 (inter) cycles for the no-DC
form, which averages from 23393 (intra) or 16612 (inter) to 3449 (intra)
or 2392 (inter) for all 32x32s together, i.e. about ~7x faster (all
tests done on ped1080p.webm).

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7f49667d83db_3396_WebVTT_capability_tester.vtt
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixes use of uninitialized memory with vlc (sample from ticket3277)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

* qatar/master:
  libopusenc: Change default frame duration to 20 ms

See: 74906d37Merged-by: Michael Niedermayer <michaelni@gmx.at>

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7fa8c49400d0_3923_audiosig.rm
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7f2785ab8669_6838_mewmew_vorbis_ssa.nut
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

* commit '9409c9bd':
  configure: Disable networking if winsock2.h is available but winsock functions aren't
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '01d245ef':
  random_seed: Rewrite the generic clock() based seed code

Conflicts:
	libavutil/random_seed.c

See: 66531c75Merged-by: Michael Niedermayer <michaelni@gmx.at>

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

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

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

20 ms is the default in the libopus encoder, and gives better
quality than 10 ms.
Signed-off-by: Martin Storsjö <martin@martin.st>

Previously, if neither of the checks for the closesocket function
succeeded, we still kept winsock2.h and networking in general
enabled.

When targeting the WinRT API subset, the winsock2.h header is
available (making the check for it succeed, giving the impression
that winsock is available), but tests that actually try to use
such a function will fail. In this case, disable the winsock2.h
feature and networking in general, as if the winsock2.h header
test would have failed in the first place.
Signed-off-by: Martin Storsjö <martin@martin.st>

The new code is faster and reuses the previous state in case of
multiple calls.

The previous code could easily end up in near-infinite loops,
if the difference between two clock() calls never was larger than
1.

This makes fate-parseutils finish in finite time when run in wine,
if CryptGenRandom isn't available (which e.g. isn't available if
targeting Windows RT/metro).

Patch originally by Michael Niedermayer but with some modifications
by Martin Storsjö.
Signed-off-by: Martin Storsjö <martin@martin.st>

* qatar/master:
  configure: Update freetype check to follow upstream

Conflicts:
	configure

Not merged, as its broken (Reported by ubitux)

See: cea5812fMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'd68dc3c9':
  drawtext: Drop pointless header

See: cea5812fMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '6892d145':
  segafilm: fix leaks if reading the header fails

Conflicts:
	libavformat/segafilm.c

See: ca5456dbMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '9cbf2d78':
  pthread_frame: unref decoded frames on failure
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'a03a642d':
  h264: do not use 422 functions for monochrome

See: 07abf13dMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '9eef9eb3':
  h264: check that execute_decode_slices() is not called too many times

Conflicts:
	libavcodec/h264.c

The check is replaced by an assert() as the mb index should not ever go out
of bounds.
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'bfd26b7c':
  h264: reject mismatching luma/chroma bit depths during sps parsing

Conflicts:
	libavcodec/h264_ps.c

See: bdeb61ccMerged-by: Michael Niedermayer <michaelni@gmx.at>

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

* commit '9a026c72':
  h264: rebuild the default ref list if the reference count changes

Conflicts:
	libavcodec/h264.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '4736d003':
  cavsdec: check ff_get_buffer() return value

Conflicts:
	libavcodec/cavsdec.c

See: eee8c94fMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '50079a6a':
  lavc: do not leak the internal frame if opening the codec fails

Conflicts:
	libavcodec/utils.c

See: 8b285f03Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '3867f371':
  lavf: remove a pointless check

Conflicts:
	libavformat/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '75647dea':
  oggparseogm: check timing variables

See: 9ed388f5Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '8058284c':
  lavc: add 422/444 YUV with alpha to align_dimensions()

Conflicts:
	libavcodec/utils.c

Only cosmetical changes happen as these formats already where in the list before
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '2f970946':
  lagarith: do not call simd functions on unaligned lines

Conflicts:
	libavcodec/lagarith.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'f4a8a008':
  sgidec: fix buffer size check in expand_rle_row()

Conflicts:
	libavcodec/sgidec.c

See: 39c56ef9Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'adb199d1':
  kgv1dec: replace forcing EMU_EDGE by a copy

Conflicts:
	libavcodec/kgv1dec.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'fe80fa53':
  4xm: replace forcing EMU_EDGE by a copy

Conflicts:
	libavcodec/4xm.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'fffca3d2':
  4xm: return a proper error code.

Conflicts:
	libavcodec/4xm.c

See: a5e382adMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '06066719':
  hevc: rename some HEVC conformance streams
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '98c0cd0b':
  hevc: add new conformance streams
Merged-by: Michael Niedermayer <michaelni@gmx.at>

The freetype tutorial suggests to use #include FT_FREETYPE_H.

Bug-Id: 616