title: Macports on OSX 10.9 - compile with -stdlib=libstdc++
body: <p>In OSX 10.9 the default <code>-stdlib</code> option for clang++ is <code>libc++</code>, so that's what Macport uses when building packages.
  Is there any way to tell Macports to use <code>libstdc++</code> instead?</p>
  
  <p>In particular I would like to build OpenCV through Macports so it's using <code>libstdc++</code>, but I imagine I'll run into a need to do so for other packages as well</p>