title: clang++, boost::spirit and c++11
body: <p>I'm using clang++ (clang-421.0.60), packaged with Xcode 4.6, and came across an issue with boost::spirit. If I compile without any flags, everything compile fine. If I compile with '-std=c++11', then I get the following error (on including of "boost/spirit/include/qi.hpp"):</p>
  
  <pre><code>In file included from test_spirit11.cpp:1:
  In file included from /usr/local/include/boost/spirit/include/qi.hpp:16:
  In file included from /usr/local/include/boost/spirit/home/qi.hpp:14:
  In file included from /usr/local/include/boost/spirit/home/qi/action.hpp:14:
  In file included from /usr/local/include/boost/spirit/home/qi/action/action.hpp:21:
  /usr/local/include/boost/spirit/home/support/action_dispatch.hpp:21:10: fatal error: 
    'type_traits' file not found
  
  #include &lt;type_traits&gt;
  </code></pre>
  
  <p>The problem is that the default library used (stdlibc++) has type_traits defined as 'tr1/type_traits', whereas boost::spirit expects just 'type_traits'. I can of course fix this problem by doing:</p>
  
  <pre><code> clang++ -std=c++11 -stdlib=libc++ &lt;...&gt;
  </code></pre>
  
  <p>While I would love to use libc++, the practicality of doing so is difficult (many libraries still use and depend on stdlibc++). Thus, I am forced to not use libc++.</p>
  
  <p>Does anyone have any suggestions on how to deal with this? I really wish that either more library maintainers support libc++ or that Apple provided a newer version of stdlibc++. It's been a major frustration to have access to new c++11 features, but not be able to fully use them due to lack of library support.</p>