gengenrtl needs to link with libintl

[DJ Delorie]

> Thus, I think we should undefine ENABLE_NLS rather than HAVE_LIBINTL_H
> to disable NLS when building generator files.  However, configure for
> libiberty needs to be modified to add an `--enable-nls' option.

Patches welcome.  It won't fix the bug, but it should avoid it.

> Similar patches should be done for getopt.c and regex.c which also
> may use NLS.

I've a pending regex.c merge from glibc that adds ENABLE_NLS.