Simply removing the WANT_AUTOCONF line makes it fail (with autoconf 2.63): ***** autoconf ***** ***** PWD: /var/tmp/portage/app-editors/emacs-21.4-r18/work/emacs-21.4 ***** autoconf aclocal.m4:30: error: m4_defn: undefined macro: _m4_divert_diversion aclocal.m4:30: the top level autom4te-2.63: /usr/bin/m4 failed with exit status: 1 @Diego: I couldn't find a tracker bug for this, is there any?
Should be fixed in -r19.