title: std::stoi doesn't exist in g++ 4.6.1 on MinGW
body: <p>I tried compiling this simple program <a href="http://ideone.com/kVcLY">on IdeOne</a> (which uses gcc 4.5.1) and on my Linux computer (which uses something like 4.6.4):</p>
  
  <pre><code>#include &lt;string&gt;
  #include &lt;iostream&gt;
  
  int main() {
       std::cout &lt;&lt; std::stoi("32") &lt;&lt; std::endl;
  }
  </code></pre>
  
  <p>And it compiles perfectly and outputs <code>32</code>. However, when I try to compile it on my windows computer with MinGW and gcc 4.6.1, I get this error:</p>
  
  <pre><code>test.cpp: In function 'int main()':
  test.cpp:5:19: error: 'stoi' is not a member of 'std'
  </code></pre>
  
  <p>The same happens with <code>std::stoul</code>, etc. Does <code>std::stoi</code> and family not exist in MinGW for some reason? I thought gcc on MinGW (sh|w)ould behave the same as on Linux.</p>