title: automake version (am__api_version) hardcoded in configure script
body: <p>I'm currently working on a Linux project using autotools. The code is submitted in SCM (Perforce) and we have the configure script, Makefile.am, Makefile.in - the usual autotools boilerplate. Recently, somebody has changed Makefile.am, but forgot to regenerate Makefile.in; when I tried to build, I got this error:</p>
  
  <pre><code>WARNING: `automake-1.11' is missing on your system.  You should only need it if
           you modified `Makefile.am', `acinclude.m4' or `configure.ac'.
           You might want to install the `Automake' and `Perl' packages.
           Grab them from any GNU archive site.
   cd . &amp;&amp; /bin/bash ./config.status Makefile depfiles
  </code></pre>
  
  <p>I see the automake version is hardcoded in the configure script (and seems to come from aclocal.m4): </p>
  
  <pre><code>am__api_version='1.11'
  </code></pre>
  
  <p>So I guess I need automake-1.11 (not 1.10, not anything newer) to regenerate the Makefile.in file. </p>
  
  <p>Why is that? Why should we be tied to a specific automake version? We're mostly building on Ubuntu 14.04, where 1.14 is the default version installed. Is there a way to tell the build system to simply use whatever version of automake is installed? Or is it safe to maybe remove the am__api_version definition from aclocal.m4? </p>