When I go to: <http://www.gnu.org/software/autoconf/manual/autoconf.html>
I see: This manual (21 September 2010) is for GNU Autoconf (version 2.68), ... So the on-line manual hasn't been updated to Autoconf 2.69. This is a pity, especially because the new version of the manual documents a lot of new portability issues with make and the shell. Thanks, Stefano