https://fedoraproject.org/wiki/Changes/PortingToModernC https://fedoraproject.org/wiki/Toolchain/PortingToModernC I have a patch in hand that builds jabberd as C99. Since jabberd is now unmaintained and the upstream repository was archived in 2019 (https://github.com/jabberd2/jabberd2), I'm filing this bug to track the changes in Fedora.
Created attachment 1957144 [details] Proposed patch
I filed a PR: https://src.fedoraproject.org/rpms/jabberd/pull-request/1