gengenrtl needs to link with libintl

[DJ Delorie]

> However, I still think there should be a better way to turn
> internationalization ON and OFF in obstack.c.  Maybe obstack
> should do something similar to gcc/intl.h.  It defines
> gettext(msgid) to (msgid) when ENABLE_NLS is undefined.

If glibc has a suitable patch, please feel free to post it to
gcc-patches for libiberty too.  I saw a similar patch for regex go by,
they might already have one for obstack.

> It seems obstack.c needs memcpy, exit (in some cases), malloc and free.

I think exit, malloc, and free are reasonably portable.