Use directly Qt::

autotests/CMakeLists.txt

@@ -12,9 +12,9 @@ macro(add_unittest _source)
     add_test(NAME ${_name} COMMAND ${_name} )
     ecm_mark_as_test(kdebugsettings-${_name})
     target_link_libraries( ${_name}
-        Qt${QT_MAJOR_VERSION}::Test
+        Qt::Test
         KF5::I18n
-        Qt${QT_MAJOR_VERSION}::Widgets
+        Qt::Widgets
         KF5::ConfigCore
         KF5::WidgetsAddons
         KF5::ItemViews

src/CMakeLists.txt

@@ -62,9 +62,9 @@ if (COMPILE_WITH_UNITY_CMAKE_SUPPORT)
 endif()
 generate_export_header(libkdebugsettings BASE_NAME libkdebugsettings)
 target_link_libraries(libkdebugsettings
-    Qt${QT_MAJOR_VERSION}::Core
+    Qt::Core
     KF5::I18n
-    Qt${QT_MAJOR_VERSION}::Widgets
+    Qt::Widgets
     KF5::WidgetsAddons
     KF5::ItemViews
     KF5::ConfigCore