title: CMake :Error in configuration process, project files may be invalid
body: <p>I am new to cmake. I am trying to build opencv using cmake 3.7.2 (64 bit)to be used in Qt.
  I am working on a windows 10 64 bit system.
  I have followed the steps given in the link:
  <a href="https://wiki.qt.io/How_to_setup_Qt_and_openCV_on_Windows" rel="nofollow noreferrer">https://wiki.qt.io/How_to_setup_Qt_and_openCV_on_Windows</a></p>
  <p>As per the instructions I installed Qt-Qt5.9-MingGW 5.3.0 32 bit.</p>
  <p>The path for MinGW is also set to C:\Qt\Tools\mingw530_32\bin.</p>
  <p>The link above shows the following instructions:</p>
  <p><a href="https://i.stack.imgur.com/CHxFd.jpg" rel="nofollow noreferrer">Compiling OpenCV</a></p>
  <p>When I followed the instructions for building opencv I got the following error after clicking &quot;Configure&quot;</p>
  <p><a href="https://i.stack.imgur.com/GHZAa.jpg" rel="nofollow noreferrer">Error message</a></p>
  <p>It would be good if someone can help me with this problem.</p>