The suse spec now uses:
%{_mandir}/man3/*.3%{?ext_man}
which defaults to .gz and fails, as we disable compression.
Redefine it to avoid a build failure:
Processing files: systemd-doc-260.2-00.noarch
error: File not found: /var/tmp/BUILD/systemd-260.2-build/BUILDROOT/usr/share/man/man3/*.3.gz