Switch include guards to #pragma once.

Components/DiskII/DiskII.hpp

@@ -6,8 +6,7 @@
 //  Copyright 2018 Thomas Harte. All rights reserved.
 //
 
-#ifndef DiskII_hpp
-#define DiskII_hpp
+#pragma once
 
 #include "../../ClockReceiver/ClockReceiver.hpp"
 #include "../../ClockReceiver/ClockingHintSource.hpp"
@@ -126,5 +125,3 @@ class DiskII :
 };
 
 }
-
-#endif /* DiskII_hpp */

Components/DiskII/DiskIIDrive.hpp

@@ -6,8 +6,7 @@
 //  Copyright © 2020 Thomas Harte. All rights reserved.
 //
 
-#ifndef DiskIIDrive_hpp
-#define DiskIIDrive_hpp
+#pragma once
 
 #include "IWM.hpp"
 
@@ -27,5 +26,3 @@ class DiskIIDrive: public IWMDrive {
 };
 
 }
-
-#endif /* DiskIIDrive_hpp */

Components/DiskII/IWM.hpp

@@ -6,8 +6,7 @@
 //  Copyright © 2019 Thomas Harte. All rights reserved.
 //
 
-#ifndef IWM_hpp
-#define IWM_hpp
+#pragma once
 
 #include "../../Activity/Observer.hpp"
 
@@ -119,7 +118,4 @@ class IWM:
 		void select_shift_mode();
 };
 
-
 }
-
-#endif /* IWM_hpp */

Components/DiskII/MacintoshDoubleDensityDrive.hpp

@@ -6,8 +6,7 @@
 //  Copyright © 2019 Thomas Harte. All rights reserved.
 //
 
-#ifndef MacintoshDoubleDensityDrive_hpp
-#define MacintoshDoubleDensityDrive_hpp
+#pragma once
 
 #include "IWM.hpp"
 
@@ -47,5 +46,3 @@ class DoubleDensityDrive: public IWMDrive {
 };
 
 }
-
-#endif /* MacintoshDoubleDensityDrive_hpp */