title: Qt 5 and OS X Mavericks issues
body: <p>I'm using Cmake to build a QT project on OS X 10.9.</p>
  
  <p>Since Mavericks, the location of the OpenGL headers seems to have changed. The folder <code>/System/Library/Frameworks/OpenGL.framework/Headers</code> is missing now, and cmake says</p>
  
  <pre><code>CMake Error at /Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake:8 (message):
    Failed to find "gl.h" in
    "/System/Library/Frameworks/OpenGL.framework/Headers"
    "/System/Library/Frameworks/AGL.framework/Headers""."
  </code></pre>
  
  <p>and asks me to provide the correct path in this variable <code>_qt5gui_OPENGL_INCLUDE_DIR</code>, which I tried with the path they apparently moved the headers to in Mavericks:</p>
  
  <pre><code>/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/OpenGL.framework/Headers
  </code></pre>
  
  <p>But I still get the following cmake error:</p>
  
  <pre><code>CMake Error at /Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfig.cmake:15 (message):
    The imported target "Qt5::Gui" references the file
  
       "/System/Library/Frameworks/OpenGL.framework/Headers"
  
    but this file does not exist.  Possible reasons include:
  
    * The file was deleted, renamed, or moved to another location.
  
    * An install or uninstall procedure did not complete successfully.
  
    * The installation package was faulty and contained
  
       "/Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake"
  
    but not all the files it references.
  
  Call Stack (most recent call first):
    /Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake:57 (_qt5_Gui_check_file_exists)
    /Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake:64 (_qt5gui_find_extra_libs)
    /Applications/Qt/5.1.1/clang_64/lib/cmake/Qt5Gui/Qt5GuiConfig.cmake:123 (include)
    CMakeLists.txt:40 (find_package)
  </code></pre>
  
  <p>Now I don't know what to do about this error, any ideas?</p>