Fix compile build against qt6

CMakeLists.txt

@@ -115,7 +115,7 @@ add_definitions(-DUSING_DYNAMIC_LIBS)
 endif(MSVC)
 
 if (HAVE_OPENBABEL AND AvogadroLibs_FOUND AND EIGEN3_FOUND)
-  find_package(Qt5OpenGL ${QT_MIN_VERSION} REQUIRED)
+  find_package(Qt${QT_MAJOR_VERSION}OpenGL ${QT_MIN_VERSION} REQUIRED)
   find_package(KF5NewStuff REQUIRED)
   # avoid compilerwarnings about redefinitions
   # todo: use check_function_exits() ?

compoundviewer/CMakeLists.txt

@@ -18,9 +18,9 @@ target_link_libraries(compoundviewer
     KF5::I18n
     KF5::WidgetsAddons
     KF5::CoreAddons
-    Qt5::OpenGL
-    Qt5::Gui
-    Qt5::Widgets
+    Qt::OpenGL
+    Qt::Gui
+    Qt::Widgets
     ${OPENBABEL_LIBRARIES}
     AvogadroQtGui
     AvogadroQtOpenGL