AP_Compass: replace header guard with pragma once

libraries/AP_Compass/AP_Compass_AK8963.h

@@ -1,6 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-#ifndef AP_Compass_AK8963_H
-#define AP_Compass_AK8963_H
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Common/AP_Common.h>
@@ -122,4 +121,3 @@ private:
     AP_HAL::I2CDriver *_i2c;
     uint8_t _addr;
 };
-#endif

libraries/AP_Compass/AP_Compass_Backend.h

@@ -18,8 +18,7 @@
   Compass driver backend class. Each supported compass sensor type
   needs to have an object derived from this class.
  */
-#ifndef __AP_COMPASS_BACKEND_H__
-#define __AP_COMPASS_BACKEND_H__
+#pragma once
 
 #include "Compass.h"
 
@@ -81,5 +80,3 @@ protected:
 private:
     void apply_corrections(Vector3f &mag, uint8_t i);
 };
-
-#endif // __AP_COMPASS_BACKEND_H__

libraries/AP_Compass/AP_Compass_HIL.h

@@ -1,6 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-#ifndef AP_Compass_HIL_H
-#define AP_Compass_HIL_H
+#pragma once
 
 #include "Compass.h"
 
@@ -19,5 +18,3 @@ public:
 private:
     uint8_t     _compass_instance[HIL_NUM_COMPASSES];
 };
-
-#endif

libraries/AP_Compass/AP_Compass_HMC5843.h

@@ -1,6 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-#ifndef AP_Compass_HMC5843_H
-#define AP_Compass_HMC5843_H
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Common/AP_Common.h>
@@ -120,5 +119,3 @@ private:
     AuxiliaryBusSlave *_slave = nullptr;
     bool _started = false;
 };
-
-#endif

libraries/AP_Compass/AP_Compass_PX4.h

@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef AP_Compass_PX4_H
-#define AP_Compass_PX4_H
+#pragma once
 
 #include "Compass.h"
 #include "AP_Compass_Backend.h"
@@ -26,6 +24,3 @@ private:
     uint32_t _count[COMPASS_MAX_INSTANCES];
     uint64_t _last_timestamp[COMPASS_MAX_INSTANCES];
 };
-
-#endif // AP_Compass_PX4_H
-

libraries/AP_Compass/Compass.h

@@ -1,6 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-#ifndef Compass_h
-#define Compass_h
+#pragma once
 
 #include <inttypes.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
@@ -417,4 +416,3 @@ private:
 #include "AP_Compass_LSM303D.h"
 #include "AP_Compass_qflight.h"
 #include "AP_Compass_QURT.h"
-#endif