Prep for C++ port

src/board.h

@@ -1,8 +1,11 @@
 // Copyright (C) 2026 Allen Hill <allenofthehills@gmail.com>
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-#ifndef BOARD_H
-#define BOARD_H
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 // Clock setup + GPIO/pin configuration. Call once, first thing at startup
 // (before any peripheral init).
@@ -11,4 +14,6 @@ void board_init(void);
 // Globally enable interrupts. Call after all peripherals are initialized.
 void board_interruptsEnable(void);
 
-#endif // BOARD_H
+#ifdef __cplusplus
+}
+#endif