On my AMD Ryzen 9 7900 workstation, the gifsave_timeout test consistently fails with:

$ meson test -C build --print-errorlogs
...
 8/12 gifsave_timeout          FAIL             2.46s   exit status 1
――― ✀ ―――
expected error return from vips_gifsave_buffer()
――――――――――

I suspect the image gets quantized/remapped within 2 seconds, so we can't guarantee that it always returns an error. The best we could do is g_assert(is_killed), which is a no-op in release builds.

Targets the 8.16 branch.