configure: clean up Altivec detection

There used to be one test for Altivec intrinsics support and a
separate test to determine which of two possible syntaxes to use
for vector literals.  Since 2008, we only support the more common
of these so the split test no longer makes sense.

This combines the tests into one and also changes the hard error on
failure to a warning.  The test can reasonably fail if no --cpu flag
is provided (or is provided with an unknown CPU) and the compiler
default target does not support Altivec.  Aborting in this case is
probably over-reacting.

Signed-off-by: Mans Rullgard <mans@mansr.com>
mjpegdec: more meaningful return values
doc: Fix syntax errors in sample Emacs config

Signed-off-by: Diego Biurrun <diego@biurrun.de>
utvideo: Rename utvideo.c to utvideodec.c

Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>
libvpxenc: use the default bitrate if not set

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
amrwbdec: Decode the fr_quality bit properly

The way this bit is decoded was accidentally flipped in b70feb405,
leading to warnings "Encountered a bad or corrupted frame" for each
decoded frame.

Signed-off-by: Martin Storsjö <martin@martin.st>
h264: vdpau: fix crash with unsupported colorspace

The h264_vdpau decoder crashed if output colorspace was not 8-bit 420.
Add a check to error out instead (current hardware does not support
other colorspaces, so successful decoding is not possible).

Signed-off-by: Martin Storsjö <martin@martin.st>
avio: add (ff)url_get_multi_file_handle() for getting more than one fd

Signed-off-by: Martin Storsjö <martin@martin.st>
rtsp.c: use ffurl_get_multi_file_handle() instead of ff_rtp_get_rtcp_file_handle()

Signed-off-by: Martin Storsjö <martin@martin.st>
rtp: remove ff_rtp_get_rtcp_file_handle().

Signed-off-by: Martin Storsjö <martin@martin.st>
rtmpdh: Do not generate the same private key every time when using libnettle

Replace mpz_random by mpz_urandomb with a random state initialization in
order to improve the randomness.

Signed-off-by: Martin Storsjö <martin@martin.st>
dvenc: don't use deprecated AVCODEC_MAX_AUDIO_FRAME_SIZE
swf(dec): replace CODEC_ID with AV_CODEC_ID
lavc: add const to AVCodec* function parameters.
lavc: add avcodec_descriptor_get_by_name().
avconv: make -shortest a per-output file option.
cmdutils: refactor -codecs option.

Make it print a list of AVCodecDescriptors.

Add new -decoders and -encoders options that print lists of decoders and
encoders respectively.
mpegvideo_enc: don't use deprecated avcodec_encode_video().
pthread: add const to AVCodec pointers

Signed-off-by: Mans Rullgard <mans@mansr.com>
libavformat: add const to AVCodec pointers

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