New error on linux

[Edward Z. Yang]

OK fixed.

Edward

Excerpts from Edward Z. Yang's message of 2015-10-27 10:36:36 -0700:
> That's simple, we can just use ifdef to test for macro appearance.
> I'll commit a fix.
> 
> Edward
> 
> Excerpts from Ben Gamari's message of 2015-10-27 04:04:42 -0700:
> > Simon Peyton Jones <simonpj at microsoft.com> writes:
> > 
> > > gcc 4.6.3
> > >
> > Alright, we'll need to figure out what to do about these differences.
> > 
> > Cheers,
> > 
> > - Ben