cmake: Make sure moc/rcc/uic are built when needed

This way you can run cmake, go directly into src/widgets
and it will build moc and rcc before QtCore (because they are needed
there) and uic before QtWidgets but not before QtCore because
it's not used there.

Without this it would get stuck creating the mocs since cmake
is not expecting the moc executable to just not be there

Change-Id: Ibcb6057bfab7a4bf823544e8f7bd128ea93d1986
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/corelib/CMakeLists.txt

@@ -239,6 +239,9 @@ add_qt_module(Core
         QT_NO_FOREACH
 )
 
+add_dependencies(Core Qt::moc)
+add_dependencies(Core Qt::rcc)
+
 configure_file(global/qconfig.cpp.in global/qconfig.cpp)
 
 # Handle QObject: Automoc does not work for this as it would

src/widgets/CMakeLists.txt

@@ -65,6 +65,8 @@ add_qt_module(Widgets
         Qt::Gui
 )
 
+add_dependencies(Widgets Qt::uic)
+
 ## Scopes:
 #####################################################################
 #