Pass the HAVE_QT* flags through the config header, like all others.

I don't know why it didn't work for the original author, but it definitely
works now.

cmake/OpenCVFindLibsGUI.cmake

@@ -24,7 +24,6 @@ if(WITH_QT)
     if(Qt5Core_FOUND AND Qt5Gui_FOUND AND Qt5Widgets_FOUND AND Qt5Test_FOUND AND Qt5Concurrent_FOUND)
       set(HAVE_QT5 ON)
       set(HAVE_QT  ON)
-      add_definitions(-DHAVE_QT)
       find_package(Qt5OpenGL)
       if(Qt5OpenGL_FOUND)
         set(QT_QTOPENGL_FOUND ON)
@@ -36,7 +35,6 @@ if(WITH_QT)
     find_package(Qt4 REQUIRED QtCore QtGui QtTest)
     if(QT4_FOUND)
       set(HAVE_QT TRUE)
-      add_definitions(-DHAVE_QT) # We need to define the macro this way, using cvconfig.h does not work
     endif()
   endif()
 endif()
@@ -61,7 +59,6 @@ if(WITH_OPENGL)
       list(APPEND OPENCV_LINKER_LIBS ${OPENGL_LIBRARIES})
       if(QT_QTOPENGL_FOUND)
         set(HAVE_QT_OPENGL TRUE)
-        add_definitions(-DHAVE_QT_OPENGL)
       else()
         ocv_include_directories(${OPENGL_INCLUDE_DIR})
       endif()