nitpicker: send pointer pos to global key handler

To enable a global key handler to implement motion gestures while a
global key is held, it needs to know the current pointer position at the
time when the global key sequence starts. This is prerequisite for
the window layouter's ability to drag windows by clicking anywhere
within the window while holding a global key.

Issue genodelabs#5403

repos/os/src/server/nitpicker/user_state.cc

@@ -234,8 +234,17 @@ void User_state::_handle_input_event(Input::Event ev)
 			global_receiver = _global_keys.global_receiver(keycode);
 
 		if (global_receiver) {
+			bool const orig_global_key_sequence = _global_key_sequence;
 			_global_key_sequence = true;
 			_input_receiver      = global_receiver;
+
+			/* deliver current pointer position at start of key sequence */
+			if (orig_global_key_sequence != _global_key_sequence)
+				_pointer.with_result(
+					[&] (Point at) {
+						Absolute_motion motion { at.x, at.y };
+						_input_receiver->submit_input_event(motion); },
+					[&] (Nowhere) { });
 		}
 
 		/*