* commit '20a8c78c':
  avconv: Do not copy extradata if source buffer is empty

This commit is a noop, see 4d02dfbdMerged-by: Clément Bœsch <u@pkh.me>

* commit '38f99017':
  vp9: Return the correct size when decoding a superframe

This commit is a noop, see c2f3715cMerged-by: Clément Bœsch <u@pkh.me>

* commit 'b2d5d6a7':
  build: Only enable symbol reduction if the compiler does proper DCE
Merged-by: Clément Bœsch <u@pkh.me>

* commit 'c5fd4b50':
  build: Simplify postprocessing of linker version script files
Merged-by: Clément Bœsch <u@pkh.me>

P1, P2, and P3 are respectively the text versions of PBM, PGM and PPM
files.

We can not obtain the buffer size using av_imgage_get_buffer_size() as
every pixel in the picture will occupy a random size between 16 and 32
bits ("4 " and "231 " are such example).

Ideally, we could look for the next header (or EOF) in the bytestream,
but this commit is meant to fix a decoding regression introduced by
48ac4532.

Fix Ticket #5670

* commit '535a742c':
  build: Change structure of the linker version script templates
Merged-by: Matthieu Bouron <matthieu.bouron@stupeflix.com>

Signed-off-by: Rick Kern <kernrj@gmail.com>

* commit '5b1b495c':
  build: Print a message when generating version scripts
Merged-by: Matthieu Bouron <matthieu.bouron@stupeflix.com>

See merge commit '39d6d361'.

* commit '1e9c5bf4':
  asm: FF_-prefix internal macros used in inline assembly

This commit is a noop as the ASM codebase differs too much between libav
and ffmpeg. The corresponding chunks will be found in the next commit.
Merged-by: Matthieu Bouron <matthieu.bouron@stupeflix.com>

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

Fixes ticket #5669.
Signed-off-by: Marton Balint <cus@passwd.hu>

Use c++98 standard instead of c++11.
Signed-off-by: Rick Kern <kernrj@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

output have been compared with official decoding tool output (dwebp)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Signed-off-by: James Almer <jamrial@gmail.com>

Signed-off-by: James Almer <jamrial@gmail.com>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

This patch also makes BlackMagic drivers v10.6.1 a hard requirement.
Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Reviewed-by: Deti Fliegl <deti@fliegl.de>
Signed-off-by: Marton Balint <cus@passwd.hu>

Fixes issues with libopenjpeg 2.1
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

* commit 'dc40a70c':
  Drop unnecessary libavutil/x86/asm.h #includes
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit '5264e7ba':
  ac3: Check the array bound before dereferencing

See d85ebea3Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'a86aa160':
  vaapi_h264: Add trivial support for low-power encoding
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'b51c7c6b':
  vaapi_h264: Fix frame_num after non-reference frames
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit '2bfa067d':
  vaapi_encode: Check config attributes before creating config
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit '6641819f':
  build: Ignore generated mapfile and remove it on distclean
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'f5c43884':
  FATE: drop the audio stream from the dxtory test
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'fe7b21c8':
  avconv: fix parsing bitstream filters

Not merged because ffmpeg_opt.c still uses the old BSF API.
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit '80fb19bc':
  avconv: fix a check for av_bsf_get_by_name() return value
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit '9f7590f4':
  avconv_vaapi: use the hwcontext device creation API
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

Improves compatibility with some MinGW variants,
see 771537ed

* commit '18c506e9':
  avconv_dxva2: use the hwcontext device creation API
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'f72db3f2':
  avconv_vdpau: use the hwcontext device creation API
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>

* commit 'b8bf9194':
  hwcontext_vaapi: implement device creation
Merged-by: Hendrik Leppkes <h.leppkes@gmail.com>