cpplib: fix -Wtrigraphs double warnings

[Geoff Keating]

"Zack Weinberg" <zackw@Stanford.EDU> writes:

> On Wed, Nov 22, 2000 at 08:22:28PM +0000, Neil Booth wrote:
> > And a testcase (Wtrigraphs.c):-
> 
> I'm not sure this will fail in the presence of the bug.  The existing
> trigraphs test should've picked it up, but it didn't.
> 
> I don't know what to do about it, though; it's a design problem with
> dg.exp.  The "excess errors" test doesn't distinguish between one copy
> of an error mesage, and multiple copies.

Are you sure you have the latest dejagnu?

I'm sure I've seen test failures in the regression tester caused
by this.

-- 
- Geoffrey Keating <geoffk@geoffk.org>