Update cross-gcc to the 8.1 GA release in Fedora 28+, possibly might need a sync up of cross-binutils as well, so the cross compiler stack matches the Fedora 28 main Fedora toolchain stack.
cross-binutils are 2.30-based for quite some time now, see https://src.fedoraproject.org/cgit/rpms/cross-binutils.git/commit/?id=197b26143198017c54fdc43eb9e613de91f547b3 And indeed bumping og cross-gcc makes perfect sense.
cross-gcc-8.1.1-3.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-9a0d2245d5
cross-gcc-8.1.1-3.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-9a0d2245d5
cross-gcc-8.1.1-3.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.