Update to 2.4.2:

version 2.4.2:
- avcodec/on2avc: Check number of channels
- avcodec/hevc: fix chroma transform_add size
- avcodec/h264: Check mode before considering mixed mode intra prediction
- avformat/mpegts: use a padded buffer in read_sl_header()
- avformat/mpegts: Check desc_len / get8() return code
- avcodec/vorbisdec: Fix off by 1 error in ptns_to_read
- sdp: add support for H.261
- avcodec/svq3: Do not memcpy AVFrame
- avcodec/smc: fix off by 1 error
- avcodec/qpeg: fix off by 1 error in MV bounds check
- avcodec/gifdec: factorize interleave end handling out
- avcodec/cinepak: fix integer underflow
- avcodec/pngdec: Check bits per pixel before setting monoblack pixel format
- avcodec/pngdec: Calculate MPNG bytewidth more defensively
- avcodec/tiff: more completely check bpp/bppcount
- avcodec/mmvideo: Bounds check 2nd line of HHV Intra blocks
- avcodec/h263dec: Fix decoding messenger.h263
- avcodec/utils: Add case for jv to avcodec_align_dimensions2()
- avcodec/mjpegdec: check bits per pixel for changes similar to dimensions
- avcodec/jpeglsdec: Check run value more completely in ls_decode_line()
- avformat/hlsenc: export inner muxer timebase
- configure: add noexecstack to linker options if supported.
- avcodec/ac3enc_template: fix out of array read
- avutil/x86/cpu: fix cpuid sub-leaf selection
- avformat/img2dec: enable generic seeking for image pipes
- avformat/img2dec: initialize pkt->pos for image pipes
- avformat/img2dec: pass error code and signal EOF
- avformat/img2dec: fix error code at EOF for pipes
- libavutil/opt: fix av_opt_set_channel_layout() to access correct memory address
- tests/fate-run.sh: Cat .err file in case of error with V>0
- avformat/riffenc: Filter out "BottomUp" in ff_put_bmp_header()
- avcodec/webp: fix default palette color 0xff000000 -> 0x00000000
- avcodec/asvenc: fix AAN scaling
- Fix compile error on arm4/arm5 platform


(wiz)