title: Making autoconf search for C++ libraries
body: <p>I'm writing my first configure.ac and need to search for a C++ library.</p>
  
  <p>I tried the following line, but when run the configure script, it finds nothing.</p>
  
  <pre><code>AC_SEARCH_LIBS([xmlpp::Document::get_root_node], [xml++-2.6])
  </code></pre>
  
  <p>Probably something is wrong with it. So, how can I make autoconf look for C++ libraries? I don't want to supply a global method (and don't think libxml++ has one either).</p>