bug#18238: Fix for DOS build when using more accurate config[.h].in

[Eli Zaretskii]

> Date: Sun, 10 Aug 2014 19:20:48 +0100
> From: Reuben Thomas <rrt@sc3d.org>
> Cc: 18238@debbugs.gnu.org
> 
> > I don't see why the suggested code is better than the existing one.
> > HAVE_GETRLIMIT means more than its name says, as you point out, so
> > DJGPP is correct in not defining one.
> >
> 
> I think I was unclear, sorry: DJGPP does define getrlimit. It is only the
> MSDOS config.in that says it is not defined. If you run ./configure, then
> it detects getrlimit, and defines HAVE_GETRLIMIT.

Then it's a bug in the configure test for getrlimit: it should not
only test for the existence of the function, but also for RLIMIT_AS
and RLIMIT_DATA it actually needs.