Adapt build system for building against qt6

CMakeLists.txt

@@ -52,7 +52,7 @@ set(AKONADI_VERSION "5.19.40")
 set(AKONADI_SEARCH_VERSION "5.19.40")
 
 set(QT_REQUIRED_VERSION "5.15.2")
-find_package(Qt5 ${QT_REQUIRED_VERSION} CONFIG REQUIRED Widgets DBus Sql Test)
+find_package(Qt${QT_MAJOR_VERSION} ${QT_REQUIRED_VERSION} CONFIG REQUIRED Widgets DBus Sql Test)
 set(MESSAGELIB_LIB_VERSION "5.19.40")
 set(LIBKDEPIM_LIB_VERSION "5.19.40")
 set(KMIME_LIB_VERSION "5.19.40")

autotests/CMakeLists.txt

@@ -7,9 +7,9 @@ macro(add_unittest _source)
     ecm_mark_as_test(akonadiconsole-${_name})
     set_tests_properties(${_name} PROPERTIES ENVIRONMENT "QT_HASH_SEED=1")
     target_link_libraries( ${_name}
-        Qt::Test
+        Qt${QT_MAJOR_VERSION}::Test
         KF5::I18n
-        Qt::Widgets
+        Qt${QT_MAJOR_VERSION}::Widgets
         KF5::ConfigCore
         KF5::WidgetsAddons
         KF5::ItemViews

src/CMakeLists.txt

@@ -148,7 +148,7 @@ target_link_libraries(libakonadiconsole
     KF5::Mime
     KF5::Contacts
     KF5::CalendarCore
-    Qt::Sql
+    Qt${QT_MAJOR_VERSION}::Sql
     KF5::Completion
     KF5::ItemViews
     KF5::TextWidgets