Stop installing the intl/ subdir sources.
* gettext-runtime/intl/Makefile.in (gettextsrcdir): Remove variable.
(DISTFILES.obsolete): Remove variable.
(install-data): Don't install nor remove anything.
(installdirs): Don't create $(gettextsrcdir).
* gettext-tools/misc/add-to-archive: Don't add the intl directory to the
archive.
* PACKAGING: Remove mention of $prefix/share/gettext/intl/ directory.
