title: Add the installation prefix of "Qt5Widgets" to CMAKE_PREFIX_PATH
body: <p>I don't know a lot about cmake, I'm trying to build a client using cmake and Qt. Getting the following error:</p>
  
  <blockquote>
    <p>CMake Error at alethzero/CMakeLists.txt:26 (find_package):   By not
    providing "FindQt5Widgets.cmake" in CMAKE_MODULE_PATH this project<br>
    has asked CMake to find a package configuration file provided by<br>
    "Qt5Widgets", but CMake did not find one.</p>
    
    <p>Could not find a package configuration file provided by "Qt5Widgets"
    with   any of the following names:</p>
  
  <pre><code>Qt5WidgetsConfig.cmake
  qt5widgets-config.cmake
  </code></pre>
    
    <p>Add the installation prefix of "Qt5Widgets" to CMAKE_PREFIX_PATH or
    set   "Qt5Widgets_DIR" to a directory containing one of the above
    files.  If   "Qt5Widgets" provides a separate development package or
    SDK, be sure it has   been installed.</p>
    
    <p>-- Configuring incomplete, errors occurred!</p>
  </blockquote>
  
  <p>As far as I understand, I need to add the QT path to CMake. How do I do it? I have Qt installed in /home/user/Programs. All the explanations I find are "just do this or that". I need the exact Terminal commands so I can just learn how to do it in the future.</p>
  
  <p>Thanks!</p>
  
  <p>UPDATE: <code>export CMAKE_PREFIX_PATH=/home/user/Programs</code> did not help me.</p>