AntennaTracker: Support new battery failsafes

AntennaTracker/GCS_Mavlink.cpp

@@ -826,4 +826,4 @@ void AP_Camera::send_feedback(mavlink_channel_t chan) {}
 /* end dummy methods to avoid having to link against AP_Camera */
 
 // dummy method to avoid linking AFS
-bool AP_AdvancedFailsafe::gcs_terminate(bool should_terminate) {return false;}
+bool AP_AdvancedFailsafe::gcs_terminate(bool should_terminate, const char *reason) {return false;}

AntennaTracker/Tracker.h

@@ -151,7 +151,9 @@ private:
 #endif
 
     // Battery Sensors
-    AP_BattMonitor battery{MASK_LOG_CURRENT};
+    AP_BattMonitor battery{MASK_LOG_CURRENT,
+                           FUNCTOR_BIND_MEMBER(&Tracker::handle_battery_failsafe, void, const char*, const int8_t),
+                           nullptr};
 
     struct Location current_loc;
 
@@ -263,6 +265,7 @@ private:
     void Log_Write_Vehicle_Startup_Messages();
     void log_init(void);
     bool should_log(uint32_t mask);
+    void handle_battery_failsafe(const char* type_str, const int8_t action);
 
 public:
     void mavlink_snoop(const mavlink_message_t* msg);

AntennaTracker/sensors.cpp

@@ -127,3 +127,10 @@ void Tracker::update_GPS(void)
     }
 }
 
+void Tracker::handle_battery_failsafe(const char* type_str, const int8_t action)
+{
+    // NOP
+    // useful failsafes in the future would include actually recalling the vehicle
+    // that is tracked before the tracker loses power to continue tracking it
+}
+