various: add missing "#pragma once"

src/basic/missing_syscall_def.h

@@ -4,6 +4,7 @@
  * Use 'ninja -C build update-syscall-tables' to download new syscall tables,
  * and 'ninja -C build update-syscall-header' to regenerate this file.
  */
+#pragma once
 
 /* Note: if this code looks strange, this is because it is derived from the same
  * template as the per-syscall blocks below. */

src/basic/missing_syscalls.py

@@ -142,6 +142,7 @@ def print_syscall_defs(syscalls, tables, out):
  * Use 'ninja -C build update-syscall-tables' to download new syscall tables,
  * and 'ninja -C build update-syscall-header' to regenerate this file.
  */
+#pragma once
 ''',
           file=out)
     print(ARCH_CHECK, file=out)

src/boot/efi/xbootldr.h

@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
 
 #include <efi.h>
 

src/network/networkd-wiphy.h

@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
 
 #include <inttypes.h>