build fixes

[Edward Z. Yang]

The ghc-api one is a known issue, I've been meaning to fix it but
haven't gotten around to it (the ghc-api test doesn't like being run
in parallel.)

Edward

Excerpts from Gabor Greif's message of 2014-08-29 19:40:58 +0100:
> Phabricator complains about these two:
> 
> Unexpected failures:
>        ghc-api                   ghcApi [exit code non-0] (normal)
>        simplCore/should_compile  T6056 [stderr mismatch] (optasm)
> 
> I doubt they are from me, as I only changed a (different) test and
> fixed some comments.
> 
> Cheers,
> 
>     Gabor
> 
> On 8/29/14, Simon Peyton Jones <simonpj at microsoft.com> wrote:
> > I've pushed patches that should finally fix the build.  (including improved
> > performance in the compiler itself!)
> > Sorry about the breakage yesterday
> > Simon
> >