AP_OpticalFlow: replace header guard with pragma once

libraries/AP_OpticalFlow/AP_OpticalFlow_HIL.h

@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef AP_OpticalFlow_HIL_H
-#define AP_OpticalFlow_HIL_H
+#pragma once
 
 #include "OpticalFlow.h"
 
@@ -17,6 +15,3 @@ public:
     // update - read latest values from sensor and fill in x,y and totals.
     void update(void);
 };
-
-#endif // AP_OpticalFlow_HIL_H
-

libraries/AP_OpticalFlow/AP_OpticalFlow_Linux.h

@@ -4,9 +4,7 @@
  * Portions of this driver were borrowed from the PX4Firmware px4flow driver which can be found here:
  *     https://github.com/PX4/Firmware/blob/master/src/drivers/px4flow/px4flow.cpp
  */
-
-#ifndef AP_OpticalFlow_Linux_H
-#define AP_OpticalFlow_Linux_H
+#pragma once
 
 #include "OpticalFlow.h"
 
@@ -82,5 +80,3 @@ private:
     uint16_t num_errors = 0;
     uint32_t last_read_ms = 0;
 };
-
-#endif

libraries/AP_OpticalFlow/AP_OpticalFlow_PX4.h

@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef AP_OpticalFlow_PX4_H
-#define AP_OpticalFlow_PX4_H
+#pragma once
 
 #include "OpticalFlow.h"
 
@@ -21,5 +19,3 @@ private:
     int         _fd;                // file descriptor for sensor
     uint64_t    _last_timestamp;    // time of last update (used to avoid processing old reports)
 };
-
-#endif

libraries/AP_OpticalFlow/OpticalFlow.h

@@ -1,5 +1,3 @@
-#ifndef __OpticalFlow_H__
-#define __OpticalFlow_H__
 /*
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,6 +12,7 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#pragma once
 
 /*
  *       OpticalFlow.h - OpticalFlow Base Class for Ardupilot
@@ -98,5 +97,3 @@ private:
 #include "AP_OpticalFlow_HIL.h"
 #include "AP_OpticalFlow_PX4.h"
 #include "AP_OpticalFlow_Linux.h"
-
-#endif

libraries/AP_OpticalFlow/OpticalFlow_backend.h

@@ -1,5 +1,3 @@
-#ifndef __OpticalFlow_backend_H__
-#define __OpticalFlow_backend_H__
 /*
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,6 +12,7 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#pragma once
 
 /*
   OpticalFlow backend class for ArduPilot
@@ -48,6 +47,3 @@ protected:
     // get the yaw angle in radians
     float _yawAngleRad(void) const { return radians(float(frontend._yawAngle_cd) * 0.01f); }
 };
-
-#endif // __OpticalFlow_backend_H__
-