(EXTRA_DIST): Add ref-add.sed.in and ref-del.sed.in.

(EXTRA_DIST): Add ref-add.sed.in and ref-del.sed.in.
(charset_alias): Define.
(install-exec-local): Factor out common code.
(uninstall-local): Split lines longer than 80.
(ref-add.sed, ref-del.sed): Remove rules... (do the following instead)
(SUFFIXES): Define.
(.sed.in.sed): New rule.  Don't redirect directly to $@.
(CLEANFILES): Add ref-add.sed and ref-del.sed.