title: Xcode 7 does not build project with c++ framework
body: <p>I can't build project with a new version of the opencv 3.0.0 framework (version 2 did not have this problem).
  Xcode 7 does not compile c++ sources as c++.</p>
  
  <p>Here's the simplest setup that is not building:</p>
  
  <ol>
  <li>Download the 3.0.0 framework from here <a href="http://netix.dl.sourceforge.net/project/opencvlibrary/opencv-ios/3.0.0/opencv2.framework.zip" rel="nofollow noreferrer">http://netix.dl.sourceforge.net/project/opencvlibrary/opencv-ios/3.0.0/opencv2.framework.zip</a></li>
  <li>Create the simplest ios project with Swift language.</li>
  <li>Drag-and-drop the framework to the project.</li>
  <li>Create the <code>Objective-C++</code> source and headers and add them to the project.</li>
  <li>Create the bridging header.</li>
  </ol>
  
  <p>Here's the setup:</p>
  
  <p><a href="https://i.stack.imgur.com/vWp0X.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vWp0X.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/nQi8C.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nQi8C.png" alt="enter image description here"></a></p>
  
  <ol start="6">
  <li>Build.</li>
  </ol>
  
  <p>And here's what the compiler says:</p>
  
  <pre><code>opencv2.framework/Headers/core/base.hpp:49:4: error: base.hpp header must be compiled as C++
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/Ak69F.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ak69F.png" alt="enter image description here"></a></p>
  
  <p>Why is that? I've got the <code>.mm</code> file and it is supposed to compile as the Objective-C++ source.</p>