https://bugs.freedesktop.org/show_bug.cgi?id=61182
--- Comment #25 from ogjerstad@gmail.com --- Not without some instructions, I have never done that before.
And, I must admit, I also downgraded llvm-libs, mesa-dri-filesystem and mesa-libxatracker. I think I had to because of dependences.
I guess I will have to build from source in that case?