Without the change the game fails to start as it fails to find it's
shared objects as:
$ NIXPKGS_ALLOW_UNFREE=1 nix build -f. ut1999 && ./result/bin/ut1999
Object not found: Class Render.Render
History: UObject::SafeLoadError <- UObject::StaticLoadClass <- UGameEngine::Init <- InitEngine <- main
Exiting due to error
After the change the game starts without problems.