libwebp-1.3.2

- 9/13/2023: version 1.3.2
  This is a binary compatible release.
  * security fix for lossless decoder (chromium: #1479274, CVE-2023-4863)

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