swscale: ppc: Hide arch-specific initialization details

Also give consistent names to init functions.
swscale: consistent names for arch-specific acceleration functions
swscale: Add some missing av_cold to arch-specific init functions
swscale: cosmetics: Drop silly camelCase from swScale function pointer name
arm: dcadsp: Move synth filter initialization to dcadsp file
arm: float_dsp: Propagate cpu_flags to vfp initialization function
arm: fmtconvert: Split armv6 fmtconvert code off from vfp code
cosmetics: Place arch initialization calls in alphabetical order
ppc: cosmetics: Consistently format CPU flag detection invocations
x86: Add and use more convenience macros to check CPU extension availability
x86: avcodec: Use convenience macros to check for CPU flags
x86: avcodec: Consistently structure CPU extension initialization
ppc: don't return a value from a function declared void

Signed-off-by: Martin Storsjö <martin@martin.st>
pcm_bluray: rename pcm-mpeg.c to pcm-bluray.c

The original idea was to collect PCM codecs that could appear in various
MPEG streams in this file. Discussion in IRC lead to the conclusion that
one codec per file would be better and stop the need for #ifdefs.
pcm_bluray: cosmetics
pcm_dvd: consolidate pieces from pcm.c and mpeg.c

Remove the header decoding for PCM audio from mpeg.c and the
20/24bit parts from pcm.c and merge them into a new decoder in
pcm-dvd.c.

The decoder has added support for samples that span multiple
packets and modified 20/24bit group decoding. Both is needed to
decode samples that have been generated with DVD-Lab Pro 2. The
decoding of 16bit PCM and two channel 24bit is identical to
before. No other samples are known to verify the correctness of
the encoding this software does.
The complete list of tested formats is
48kHz/16bit/2-8 channels
48kHz/24bit/2-5 channels
96kHz/16bit/2-4 channels
96kHz/24bit/2 channels

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

The pixel format tables are never modified, mark them as constant.

Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.eu>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
configure: Add docdir configuration option

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
pcm-dvd: Fix build on big endian

Signed-off-by: Martin Storsjö <martin@martin.st>
vcr1: add sanity checks

Fixes invalid reads with corrupted files.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org