title: why i failed to build autoconf with autoconf2.6x, its version is newer  than 2.6 anyhow
body: <p>my system is centos based.</p>
  
  <p>the reason i try to build autoconf is that someone told me i can try to build it in order to solve the other problem, you may find the motivation with this link <a href="https://stackoverflow.com/questions/12136934/why-autogen-sh-failed-even-with-the-correct-autoconf#comment16480229_12136934">why autogen.sh failed even with the correct autoconf?</a></p>
  
  <pre><code>[mirror@home auto]$ cd autoconf/
  [mirror@home autoconf]$ ls
  AUTHORS    cfg.mk       ChangeLog.3        COPYINGv3    lib          man           README-hacking
  bin        ChangeLog.0  configure.ac       doc          m4           NEWS          tests
  BUGS       ChangeLog.1  COPYING            GNUmakefile  maint.mk     README        THANKS
  build-aux  ChangeLog.2  COPYING.EXCEPTION  HACKING      Makefile.am  README-alpha  TODO
  [mirror@home autoconf]$ autoreconf -iv
  autoreconf: Entering directory `.'
  autoreconf: configure.ac: not using Gettext
  autoreconf: running: aclocal -I m4
  configure.ac:20: error: Autoconf version 2.60 or higher is required
  configure.ac:20: the top level
  autom4te: /usr/bin/m4 failed with exit status: 63
  aclocal: autom4te failed with exit status: 63
  autoreconf: aclocal failed with exit status: 63
  </code></pre>
  
  <p>//  i have autoreconf2.6x on my system, its version si higher than 2.6, but still failed to build, why?</p>
  
  <pre><code>[mirror@home autoconf]$ autore
  autoreconf      autoreconf2.59  autoreconf2.6x  autorespond
  [mirror@home autoconf]$ autore
  autoreconf      autoreconf2.59  autoreconf2.6x  autorespond
  [mirror@home autoconf]$ autoreconf2.6x -iv
  
  
  [mirror@home autoconf]$ autoconf2.6x --version
  autoconf (GNU Autoconf) 2.63
  Copyright (C) 2008 Free Software Foundation, Inc.
  License GPLv2+: GNU GPL version 2 or later
  &lt;http://gnu.org/licenses/old-licenses/gpl-2.0.html&gt;
  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.
  </code></pre>
  
  <p>still failed to build autoconf, what i should do in order to build it? </p>
  
  <pre><code>[mirror@home autoconf]$ ./configure
  bash: ./configure: No such file or directory
  [mirror@home autoconf]$ autoconf
  configure.ac:29: error: possibly undefined macro: AM_INIT_AUTOMAKE
        If this token and others are legitimate, please use m4_pattern_allow.
        See the Autoconf documentation.
  configure.ac:117: error: possibly undefined macro: AC_PROG_GNU_M4
  configure.ac:124: error: possibly undefined macro: AM_MISSING_PROG
  configure.ac:187: error: possibly undefined macro: AM_PATH_LISPDIR
  configure.ac:201: error: possibly undefined macro: AC_PROG_MAKE_CASE_SENSITIVE
  [mirror@home autoconf]$ autoconf2.
  autoconf2.59  autoconf2.6x
  [mirror@home autoconf]$ autoconf2.6x
  
  [mirror@home autoconf]$ ./configure --prefix=$HOME/ins/ins_auto
  
  
  [mirror@home autoconf]$ autoreconf2.6x
  configure.ac:20: error: Autoconf version 2.60 or higher is required
  configure.ac:20: the top level
  autom4te: /usr/bin/m4 failed with exit status: 63
  aclocal: autom4te failed with exit status: 63
  autoreconf2.6x: aclocal failed with exit status: 63
  </code></pre>