[llvm-dev] Is it possible to build OpenMP without using /usr/bin/cc ? (this breaks my build)

[ardi via llvm-dev]

I'm trying to build clang 3.8.0, with openmp support. When it arrives
to building the openmp code, it tries to use /usr/bin/cc (why is that
hardcoded?) and it of course completely breaks my build, as my
/usr/bin/cc doesn't support C++11, and I'm building the llvm 3.8.0
tree with my own built clang 3.4.2.

Can I tell llvm 3.8.0 to build openmp support honoring the CXX
compiler specified in cmake options?

How?

Thanks a lot!