AP_Scheduler: fix examples

libraries/AP_Scheduler/examples/Scheduler_test/Scheduler_test.cpp

@@ -8,6 +8,12 @@
 #include <AP_Scheduler/AP_Scheduler.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include <AP_Logger/AP_Logger.h>
+#include <GCS_MAVLink/GCS_Dummy.h>
+
+const struct AP_Param::GroupInfo        GCS_MAVLINK_Parameters::var_info[] = {
+    AP_GROUPEND
+};
+GCS_Dummy _gcs;
 
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();