I'm using Guix System.

The different versions of llvm were a good hunch, unfortunately the
offending programs (ungoogled-chromium and ioquake3) use the same
/gnu/store/slhclazbx16ij6kyggz667sycmyy9iii-llvm-7.0.1.

-- 
Pierre Neidhardt
https://ambrevar.xyz/