enforce #ifndef __HEADER_H instead of #pragma once, for code consitency and better portability (#2296)

firmware/application/portapack.hpp

@@ -19,7 +19,8 @@
  * Boston, MA 02110-1301, USA.
  */
 
-#pragma once
+#ifndef __PORTAPACK_H
+#define __PORTAPACK_H
 
 #include "portapack_io.hpp"
 
@@ -85,3 +86,5 @@ Backlight* backlight();
 extern bool async_tx_enabled;  // this is for serial tx things, globally
 
 } /* namespace portapack */
+
+#endif