libwebp-1.4.0

- 4/12/2024: version 1.4.0
  This is a binary compatible release.
  * API changes:
    - libwebpmux: WebPAnimEncoderSetChunk, WebPAnimEncoderGetChunk,
                  WebPAnimEncoderDeleteChunk
    - libsharpyuv: SharpYuvOptionsInit, SharpYuvConvertWithOptions
    - extras: SharpYuvEstimate420Risk
  * further security related hardening in libwebp & examples
  * some minor optimizations in the lossless encoder
  * added WEBP_NODISCARD to report unused result warnings; enable with
    -DWEBP_ENABLE_NODISCARD=1
  * improvements and corrections in webp-container-spec.txt and
    webp-lossless-bitstream-spec.txt (#611)
  * miscellaneous warning, bug & build fixes (#615, #619, #632, #635)

1. 7c76255 autoconf: update ax_pthread.m4 by James Zern · 12 years ago
2. 1d40a8b configure: add pthread detection by James Zern · 13 years ago
3. b247a3b Create the m4 directory, and also place .gitignore in there for libtool. by Pascal Massimino · 15 years ago