Building GHC head with clang on Mavericks

[Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=)]

Hi SimonM,

> But I'm not sure about this fix.  I'm happy to merge in fixes for Mac
> in general, but in this case we seem to lose the line pragmas, which
> are actually useful (error messages will point to the original source,
> instead of some preprocessed file).

Yes. If we can find another solution which keeps line markers, it is
much better, anyway.

But this patch effects templates only. When a template is included
into an HS file (genearted from a '.x' file), the position is
shifted. So, I'm not sure that line markers are important as you
think.

--Kazu