Comment # 3 on bug 88925 from dex+fdobugzilla@dragonslave.de

(In reply to Michel Dänzer from comment #2)
> Sounds like bug 80419.

Possible. But the game worked fine until about start of the year. I think I may
still have the packaged versions of llvm and mesa from then and perhaps I can
confirm this.

I strongly suspect LLVM being the culprit here.