libintl: Remove conditionals for libglocale.

libintl: Remove conditionals for libglocale.

libglocale was a short-lived project in 2005 that was never completed.

* gettext-runtime/intl/dcigettext.c: Assume IN_LIBGLOCALE is not defined.
* gettext-runtime/intl/libgnuintl.in.h: Likewise.
* gettext-runtime/intl/loadmsgcat.c: Likewise.
* gettext-runtime/intl/localealias.c: Likewise.
* gettext-runtime/intl/plural-exp.h: Likewise.
* gettext-runtime/intl/gettextP.h: Likewise.
(gl_dcigettext): Remove declaration.
* gettext-runtime/intl/Makefile.am (libgnuintl.h, libintl.h): Remove the
IN_LIBGLOCALE handling.