title: Not able to link to Qt 5.9.2, CMake always links to system installed 5.5.1
body: <p>I'm trying to upgrade my project to Qt 5.9.2 since I believe Qt 5.9 has better C++17 compatibility than 5.5 (default in Ubuntu 16.04)</p>
  
  <p>I installed 5.9.2 using the online installer in my home directory and set <code>CMAKE_PREFIX_PATH</code> to <code>/home/karnik/Tools/Qt/5.9.2/gcc_64/libs/cmake</code> but <code>find_package(Qt5 5.9.2 COMPONENTS Widgets REQUIRED)</code> reported the error,</p>
  
  <pre><code>CMake Error at CMakeLists.txt:75 (FIND_PACKAGE):
    Could not find a configuration file for package "Qt5" that is compatible
    with requested version "5.9".
  
    The following configuration files were considered but not accepted:
  
     /usr/lib/x86_64-linux-gnu/cmake/Qt5/Qt5Config.cmake, version: 5.5.1
  </code></pre>
  
  <p>I also tried setting it to just <code>/home/karnik/Tools/Qt/5.9.2</code></p>
  
  <p>I then set <code>Qt5_DIR</code> inside my CMakeLists.txt to <code>/home/karnik/Tools/Qt/5.9.2/gcc_64/lib/cmake/Qt5/</code> and the error got solved but <code>MESSAGE("Qt Version is " ${Qt5Widgets_VERSION})</code> showed that it was still using 5.5.1.</p>
  
  <p>I then set <code>Qt5Widgets_DIR</code> to <code>/home/karnik/Tools/Qt/5.9.2/gcc_64/lib/cmake/Qt5Widgets/</code> and the version showed 5.9.2. </p>
  
  <p>But weirdly, <code>MESSAGE(${Qt5Widgets_INCLUDE_DIRS})</code> showed that it was still pointing to the old files inside /usr/include</p>
  
  <blockquote>
    <p>/usr/include/x86_64-linux-gnu/qt5//usr/include/x86_64-linux-gnu/qt5/QtWidgets/usr/include/x86_64-linux-gnu/qt5/QtGui/usr/include/x86_64-linux-gnu/qt5/QtCore/usr/lib/x86_64-linux-gnu/qt5//mkspecs/linux-g++-64/usr/include</p>
  </blockquote>
  
  <p>How can I get it to point to the right libraries?</p>
  
  <p>TIA!</p>