Comment # 16 on bug 99923 from Christoph Schwerdtfeger

I can confirm that if I recompile the Debian sources with LLVM 4.0 it's not
working (the lighting bug is present) but if I set LLVM to 3.9 it's working
correctly (lighting bug is NOT present).

I was using LLVM 4.0.1 (1:4.0.1~+rc3-1) from the Debian archives to build Mesa
(17.1.2-2) with the bug and LLVM 3.9.1 (3.9.1-10) from the Debian archives to
build Mesa without the bug.