title: How does one include TR1?
body: <p>Different compilers seem to have different ideas about TR1. G++ only seems to accept includes of the type:</p>
  
  <pre><code>#include &lt;tr1/unordered_map&gt;
  #include &lt;tr1/memory&gt;
  ...
  </code></pre>
  
  <p>While Microsofts compiler only accept:</p>
  
  <pre><code>#include &lt;unordered_map&gt;
  #include &lt;memory&gt;
  ...
  </code></pre>
  
  <p>As for as I understand TR1, the Microsoft way is the correct one.</p>
  
  <p>Is there a way to get G++ to accept the second version? 
  How does one in general handle TR1 in a portable way?</p>