title: Error using libraries provided by CGAL with qt creator
body: <p>I'm currently trying to use the cgal library in a project in qt creator (on windows). I'm all new to this ide and also to c++ but cgal offers some functionality i'd like to test. I tried to run a cgal example in qt creator in order to find out if the library is included correctly. Unfortunately i get the error message: 'enable_if_t' in namespace 'std' does not name a template type. I also get some warnings about an unused but set parameter <a href="https://i.stack.imgur.com/huTdU.png" rel="nofollow noreferrer">error messages</a>.  </p>
  
  <p>The code i'd like to run is an example from CGAL:</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;CGAL/Simple_cartesian.h&gt;
  
  typedef CGAL::Simple_cartesian&lt;double&gt; Kernel;
  typedef Kernel::Point_2 Point_2;
  typedef Kernel::Segment_2 Segment_2;
  
  int main()
  {
    Point_2 p(1,1), q(10,10);
    std::cout &lt;&lt; "p = " &lt;&lt; p &lt;&lt; std::endl;
    std::cout &lt;&lt; "q = " &lt;&lt; q.x() &lt;&lt; " " &lt;&lt; q.y() &lt;&lt; std::endl;
    std::cout &lt;&lt; "sqdist(p,q) = "
              &lt;&lt; CGAL::squared_distance(p,q) &lt;&lt; std::endl;
  
    Segment_2 s(p,q);
    Point_2 m(5, 9);
  
    std::cout &lt;&lt; "m = " &lt;&lt; m &lt;&lt; std::endl;
    std::cout &lt;&lt; "sqdist(Segment_2(p,q), m) = "
              &lt;&lt; CGAL::squared_distance(s,m) &lt;&lt; std::endl;
    std::cout &lt;&lt; "p, q, and m ";
    switch (CGAL::orientation(p,q,m)){
    case CGAL::COLLINEAR:
      std::cout &lt;&lt; "are collinear\n";
      break;
    case CGAL::LEFT_TURN:
      std::cout &lt;&lt; "make a left turn\n";
      break;
    case CGAL::RIGHT_TURN:
      std::cout &lt;&lt; "make a right turn\n";
      break;
    }
    std::cout &lt;&lt; " midpoint(p,q) = " &lt;&lt; CGAL::midpoint(p,q) &lt;&lt; std::endl;
    return 0;
  }
  </code></pre>
  
  <p>My .pro file: </p>
  
  <pre><code>QT -= gui
  
  CONFIG += c++11 console
  CONFIG -= app_bundle
  
  DEFINES += QT_DEPRECATED_WARNINGS
  
  INCLUDEPATH += C:\dev\CGAL-5.0-beta2\include
  INCLUDEPATH += C:\dev\libboost_1_71_0
  INCLUDEPATH += C:\dev\libboost_1_71_0\lib64-msvc-14.2
  INCLUDEPATH += C:\dev\CGAL-5.0-beta2\auxiliary\gmp\include
  INCLUDEPATH += C:\dev\CGAL-5.0-beta2\auxiliary\gmp
  INCLUDEPATH += C:\dev\vtk\include\vtk-8.2
  INCLUDEPATH += C:\dev\vtk\include
  
  LIBS += C:\dev\libboost_1_71_0\lib64-msvc-14.2
  LIBS += C:\dev\vtk\lib
  LIBS += C:\dev\CGAL-5.0-beta2\auxiliary\gmp\lib
  
  
  SOURCES += \
          main.cpp
  
  qnx: target.path = /tmp/$${TARGET}/bin
  else: unix:!android: target.path = /opt/$${TARGET}/bin
  !isEmpty(target.path): INSTALLS += target
  </code></pre>
  
  <p>Thanks for your help in advance</p>