The testsuite of ffmpeg fails if compilied with zlib-ng because some of
the created videos/ images use zlib compression which is different and
produces a different checksum then. The patch attached has been
backported to the 7.1 release. It originates from
https://patchwork.ffmpeg.org/project/ffmpeg/patch/20241019133358.9958-1-jamrial@gmail.com/

I haven't found any bug report belonging to this.

Sebastian