This change seems to cause the package to fail the build. Before your change, this is a build warning not an error.
dh_auto_build -- CC=valac make -j8 "INSTALL=install --strip-program=true" CC=valac make[2]: Entering directory '/<<PKGBUILDDIR>>' valac --pkg folks aggregate-avatars.vala aggregate-avatars.vala:53.3-53.41: warning: unhandled error `GLib.Error' 53 | cache_dir.make_directory_with_parents(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Unknown option -I/usr/include/glib-2.0 Run 'valac --help' to see a full list of available command line options. error: cc exited with status 256 Compilation failed: 1 error(s), 1 warning(s) By the way, I am pushing a 40.0-4 upload to Unstable now. But this is a QA package so you're welcome to directly upload a fix for this issue. Thank you, Jeremy Bícha