Fix PR i18n/761.
	* Makefile.in (.SUFFIXES): Add po .gmo, and .pox.
	(.PHONY): Add all-po install-po, uninstall-po, clean-po,
	$(PACKAGE).pot and update-po.
	(all-po, .po.gmo, .po.pox, install-po, $(PACKAGE).pot)
	(po/$(PACKAGE).pot, clean-po, uninstall-po, install-po)
	(update-po): New rules.
	(localedir): Define using autoconf.
	(diststuff): Add $(PACKAGE).pot and $(CATALOGS)
	(GDB_CFLAGS): Define LOCALEDIR using $(localedir).
	(XGETTEXT, GMSGFMT, MSGMERGE, PACKAGE, CATALOGS): Define.
	* configure.in: Generate CATALOGS and LINGUAS from contents of
	src/gdb/po/ directory.  Set @localedir@ in Makefile.in.
	* configure: Re-generate.
	* po/gdbtext: New file