linking against OpenGL from Qt5 is not necessary

CMakeLists.txt

@@ -273,7 +273,7 @@ endif()
 if (ENABLE_GUI)
   find_package(Qt5Widgets REQUIRED)
   find_package(Qt5OpenGL REQUIRED)
-  set(QT_LIBRARIES ${QT_LIBRARIES} Qt5::OpenGL Qt5::Gui Qt5::Widgets Qt5::Core)
+  set(QT_LIBRARIES ${QT_LIBRARIES} Qt5::Gui Qt5::Widgets Qt5::Core)
   ost_find_python_module(sip)
   ost_find_python_module(PyQt5)
 endif()