[llvm] r201608 - Fix PR18743.

[Rafael Espíndola]

> How is it failing? I just finishing building a stage2 but I was using
> cmake (and c++11).
>
> I started a configure bootstrap using "--enable-optimized
> --disable-compiler-version-checks --disable-assertions". I have now
> also included compiler-rt and libcxx in the bootstrap by checking them
> out in projects/.  Can you think of something else in your setup that
> might make a difference?

Stage3 of a combined llvm+clang+compiler-rt+libcxx just finished
building without a problem in here :-(

Cheers,
Rafael