Fix mismatched aliased event and event stub function prototypes.

lib/lufa/Demos/Device/ClassDriver/VirtualSerialMouse/VirtualSerialMouse.c

@@ -279,4 +279,6 @@ void EVENT_CDC_Device_ControLineStateChanged(USB_ClassInfo_CDC_Device_t *const C
 	   in the pending data from the USB endpoints.
 	*/
 	bool HostReady = (CDCInterfaceInfo->State.ControlLineStates.HostToDevice & CDC_CONTROL_LINE_OUT_DTR) != 0;
+
+	(void)HostReady;
 }