title: Compilation of OpenCV 3.1.0 videoio error
body: <p>Im trying to compile Opencv 3.1.0 with MingW 4.9.2 but i have the follow error</p>
  
  <pre><code>modules\videoio\CMakeFiles\opencv_videoio.dir\build.make:187: recipe for target
  'modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_dshow.cpp.obj' failed
  mingw32-make[2]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_dsho
  w.cpp.obj] Error 1
  CMakeFiles\Makefile2:4340: recipe for target 'modules/videoio/CMakeFiles/opencv_
  videoio.dir/all' failed
  mingw32-make[1]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2
  
  makefile:159: recipe for target 'all' failed
  mingw32-make: *** [all] Error 2
  </code></pre>
  
  <p>I found that is a OpenCV build error during cap_dshow.cpp build. The solution showed <a href="http://visp-doc.inria.fr/doxygen/visp-daily/tutorial-install-win81-mingw64.html" rel="nofollow noreferrer">here</a> is no necessary because the file in Opencv 3.1 is already fixed.</p>
  
  <p>During Cmake phase i've changed this (trough Cmake GUI 3.4.3), but doesnt work </p>
  
  <pre><code>CMAKE_BUILD_TYPE = Debug
  WITH_EIGEN = 0
  WITH_OPENGL = 0
  WITH_IPP = 0
  WITH_QT = 1
  </code></pre>
  
  <p>I've tried the solution given in <a href="https://stackoverflow.com/questions/27828740/opencv-3-0-videoio-error">this post</a>, but doesnt work neither</p>
  
  <pre><code>add_extra_compiler_option(-Werror=non-virtual-dtor)
  </code></pre>
  
  <p>My intention is work with C++, Opencv and the GUI designer of QT. I have installed the library qt-5.4.0-x64-mingw492r0-sjlj, it comes with its own MingW 4.9.2. 
  (PS/for another proyect i've compiled Opencv3.1.0 with Mingw 4.9.3 and its works perfectly)</p>
  
  <p>Can anybody helpme please!!! </p>