title: why autogen.sh failed even with the correct autoconf?
body: <p>autogen.sh failed, the output shows that i need an autoconf of higher version. but in fact i have a 2.6x autoconf....</p>
  
  <p>why it still failed?</p>
  
  <pre><code>[mirror@home 4]$ ./autogen.sh
  + autoreconf -i -f -v
  autoreconf: Entering directory `.'
  autoreconf: configure.in: not using Gettext
  autoreconf: running: aclocal --force -I m4
  configure.in:4: error: Autoconf version 2.60 or higher is required
  configure.in:4: 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>// content in configure:4<br>
  it's AC_PREREQ(2.60)</p>
  
  <pre><code>[mirror@home 4]$ autoconf
  autoconf      autoconf2.59  autoconf2.6x
  [mirror@home 4]$ autoconf
  [mirror@home 4]$ ls -l autocon
  [mirror@home 4]$ ls /usr/bin/autoconf* -l
  lrwxrwxrwx 1 root root    12 Aug 27 13:55 /usr/bin/autoconf -&gt; autoconf2.6x
  -rwxr-xr-x 1 root root  7663 Jan  6  2007 /usr/bin/autoconf2.59
  -rwxr-xr-x 1 root root 14635 Feb  3  2011 /usr/bin/autoconf2.6x
  </code></pre>
  
  <p>2.63 > 2.60, but autogen failed, it's really confusing:(</p>
  
  <pre><code>[mirror@home 4]$ autoconf --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>more details:</p>
  
  <pre><code>    autoreconf --version
      autoreconf (GNU Autoconf) 2.59
  </code></pre>
  
  <p>what i want to know is why autogen.sh failed? </p>