Archlinux default is gcc . Anyone who set clang as default compiler on archlinux should know how they achieved it and be able to reverse it.
Incase you're on some other distro that sets clang as default compiler, you'll need to ask on their support channels how to build with gcc.
Assuming you're on archlinux and don't know how to revert to defaults : setup clean chroot building. see https://wiki.archlinux.org/title/DeveloperWiki:Building_in_a_clean_chroot
Another option is not to build from source but use a nightly binary provided by upstream, see https://redfortune.de/openmw/nightly/?C=M;O=D
Pinned Comments
Lone_Wolf commented on 2022-06-17 10:07 (UTC)
openmw-git has been found to require a sizable amount of temporary space during building.
The available amount depends on system specifics so is different for all systems. In case build fails with "no space left on device" you may be bitten by this.
See https://bbs.archlinux.org/viewtopic.php?id=277304 for details and possible solutions.
bwrsandman commented on 2016-09-24 14:59 (UTC) (edited on 2018-11-22 17:28 (UTC) by bwrsandman)
Please refrain from flagging the git version as out date when a new release comes out. The git aur packages update their version on install time based on the tags of the git repo.
Keep in mind that this is a VCS package and it is meant to be in line with the latest master which might not always work. It is not meant to follow the release pattern in any particularly smart way and assumes that upstream maintains their tags consistently.
For the newest release, the correct page is https://www.archlinux.org/packages/?q=openmw