[PATCH libxtrans v2] configure: Also add -D_DEFAULT_SOURCE to .pc cflags to shut up glibc warnings

[Mark Kettenis]

> From: Hans de Goede <hdegoede at redhat.com>
> Date: Tue, 25 Mar 2014 15:16:57 +0100
> 
> I've discussed this with the glibc developers and the prefered way of fixing
> this is by also defining _DEFAULT_SOURCE which is the new way of stating
> _BSD_SOURCE / _SVID_SOURCE .

Sounds like a reasonable compromise to me.  Still think that what the
glibc developers did is unhelpful though.

Reviewed-by: Mark Kettenis <kettenis at openbsd.org>