elements/components/fontconfig.bst: Update to 2.13.92 + critical patches

This matches what is being integrated in Fedora31 at the moment, See https://src.fedoraproject.org/rpms/fontconfig/tree/a2ef9569f548a65b3e0ff48586fc6f690193db54

git describe didn't output the 2.13.92 because for some reason the maintainer decided to tag 2.13.92 outside the branch

Keep track of the rc for now

Hopefully fix #724 (closed)