GCS_MAVLink: support MAV_CMD_FIXED_MAG_CAL_YAW

libraries/GCS_MAVLink/GCS.h

@@ -417,6 +417,8 @@ protected:
 
     void handle_optical_flow(const mavlink_message_t &msg);
 
+    MAV_RESULT handle_fixed_mag_cal_yaw(const mavlink_command_long_t &packet);
+
     // vehicle-overridable message send function
     virtual bool try_send_message(enum ap_message id);
     virtual void send_global_position_int();

libraries/GCS_MAVLink/GCS_Common.cpp

@@ -3012,6 +3012,19 @@ void GCS_MAVLINK::handle_optical_flow(const mavlink_message_t &msg)
     optflow->handle_msg(msg);
 }
 
+
+/*
+  handle MAV_CMD_FIXED_MAG_CAL_YAW
+ */
+MAV_RESULT GCS_MAVLINK::handle_fixed_mag_cal_yaw(const mavlink_command_long_t &packet)
+{
+    Compass &compass = AP::compass();
+    return compass.mag_cal_fixed_yaw(packet.param1,
+                                     uint8_t(packet.param2),
+                                     packet.param3,
+                                     packet.param4);
+}
+
 /*
   handle messages which don't require vehicle specific data
  */
@@ -3731,6 +3744,10 @@ MAV_RESULT GCS_MAVLINK::handle_command_long_packet(const mavlink_command_long_t
 
         return MAV_RESULT_UNSUPPORTED;
 
+    case MAV_CMD_FIXED_MAG_CAL_YAW:
+        result = handle_fixed_mag_cal_yaw(packet);
+        break;
+        
     default:
         result = MAV_RESULT_UNSUPPORTED;
         break;