Finalized intl-update patches

  * intl: Remove directory.  Replaced with out-of-tree GNU gettext.
  * .gitignore: Add '/gettext*'.
  * configure.ac (host_libs): Replace intl with gettext. (hbaseargs, bbaseargs, baseargs): Split baseargs into {h,b}baseargs. (skip_barg): New flag.  Skips appending current flag to bbaseargs. <library exemptions>: Exempt --with-libintl-{type,prefix} from target and build machine argument passing.
  * configure: Regenerate.
  * Makefile.def (host_modules): Replace intl module with gettext module. (configure-ld): Depend on configure-gettext.
  * Makefile.in: Regenerate.
  * src-release.sh: Remove references to the intl/ directory.