APNG patch for libpng
Linux version of the patch, with LF line endings:
libpng-1.6.49-apng.patch.gz
Windows version of the patch, with CR+LF line endings:
libpng-1.6.49-apng.zip
Usage
Unpack the patch from archive into libpng directory, and run this command in libpng directory:
patch -p0 <libpng-1.6.49-apng.patch
Alternative source
https://dxr.mozilla.org/mozilla-central/source/media/libpng/apng.patch