Drop autoconf requirement from 2.60 back to 2.59.
Drop autoconf requirement from 2.60 back to 2.59.

AC_PRESERVE_HELP_ORDER, AC_PROG_MKDIR_P and AC_PROG_SED are
only available in 2.60, but it's not important enough to prevent
autoconf 2.59 (still used in some distribs) from working here
(so that we can use SVN checkouts on some machines).

Thanks to m4_ifdef, AC_PRESERVE_HELP_ORDER is just ignored if
autoconf'ing with 2.59, while AC_PROG_MKDIR_P and AC_PROG_SED
are poorly re-emulated.

Tarballs are still generated with recent autoconf anyway.

git-svn-id: 29c1264a5cf5e3532df57b06678e7347571c1a3c@2810 f1ba3bf5-cb5c-402b-92a9-7c6bdc83a356

ananos/open-mx,ananos/xen2mx,ananos/xen2mx,ananos/xen2mx,ananos/open-mx,ananos/open-mx,ananos/xen2mx