Failure to boostrap bison from git repository

[Stefano Lattarini]

Hello.

I'm consistently failing at bootstrapping Bison from the official git
repository.

The bootstrap script sucessfully brings up the gnulib machinery, but
then it fails at "autoreconf" time with the following error:

 ...
 autoreconf: running: aclocal --force -I m4
 autoreconf: configure.ac: tracing
 autoreconf: configure.ac: not using Libtool
 autoreconf: running: /usr/bin/autoconf --force
 configure.ac:110: error: possibly undefined macro: AC_PROG_GNU_M4
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
 autoreconf: /usr/bin/autoconf failed with exit status: 1

More info about the build system:

 $ git describe
 v2.4-597-g2880104

 $ uname -orsm
 Linux 2.6.30-2-686 i686 GNU/Linux

 $ lsb_release -idr
 Distributor ID: Debian
 Description:    Debian GNU/Linux testing/unstable
 Release:        testing/unstable

 $ aclocal --version
 aclocal (GNU automake) 1.11.1
 Copyright (C) 2009 Free Software Foundation, Inc.
 License GPLv2+: GNU GPL version 2 or later 
<http://gnu.org/licenses/gpl-2.0.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.
 Written by Tom Tromey <address@hidden>
        and Alexandre Duret-Lutz <address@hidden>.
 
 $ autoconf --version
 autoconf (GNU Autoconf) 2.68
 Copyright (C) 2010 Free Software Foundation, Inc.
 License GPLv3+/Autoconf: GNU GPL version 3 or later
 <http://gnu.org/licenses/gpl.html>, <http://gnu.org/licenses/exceptions.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.
 Written by David J. MacKenzie and Akim Demaille.

Please let me know if you need more information, or if you think I'm doing
something wrong (in which case, advice would be really appreciated).

Regards,
  Stefano