autoreconf thinks I'm not using libtool

[Peter Johansson]

Hello,

I experience that autoreconf, for some reason, thinks I'm not using 
libtool. I slimmed down my configure.ac to the following:

AC_INIT([1.0], [hello])
AM_INIT_AUTOMAKE([foreign])
AC_LANG([C++])
AC_PROG_CXX
AC_PROG_LIBTOOL
AC_CONFIG_FILES([Makefile])
AC_OUTPUT

and when I issue `autoreconf -isvf' I get

autoreconf: Entering directory `.'
autoreconf: configure.ac: not using Gettext
autoreconf: running: aclocal --force
autoreconf: configure.ac: tracing
autoreconf: configure.ac: not using Libtool
autoreconf: running: /opt/local/bin/autoconf --force
configure.ac:5: error: possibly undefined macro: AC_PROG_LIBTOOL
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
autoreconf: /opt/local/bin/autoconf failed with exit status: 1

I use Autoconf 2.65, Automake 1.11.1 and libtool 2.2.6b. The tools are 
all installed via port on a Mac OSX 10.4 in case that matters.

Please let me know what addition information would be useful.

Thanks,
Peter