Building GHC head with clang on Mavericks

[Sven Panne]

Although it is not really GHC-related, this thread is sufficiently
close to the problem described in
https://github.com/haskell-opengl/OpenGLRaw/issues/18: AFAICT, Mac OS
X 10.9's clang doesn't really honor -traditional, so what can I do to
make things work with recent Macs without breaking all other
platforms? I guess the right #if in
https://github.com/haskell-opengl/OpenGLRaw/blob/master/include/HsOpenGLRaw.h
will do the trick, but I don't have access to a Mac. Hints are highly
appreciated, the whole current Mac situation is a bit of a mystery to
me...

Cheers,
   S.