Even though many of those scripts are very simple, it is easier to include the header than to try to say whether each of those files is trivial enough not to require one.
The files in this directory are copied from current kernel master (b06ed1e7a2fa9b636f368a9e97c3c8877623f8b2) or WireGuard master (8416093498ac2c754536dad4757c5d86c9ba8809), and the following modifications are applied: - btrfs.h: drop '__user' attributes - if.h: drop '#include <linux/compiler.h>' and '__user' attributes