diff --git a/libc/include/arpa/ftp.h b/libc/include/arpa/ftp.h
index 081c037..fecbf7f 100644
--- a/libc/include/arpa/ftp.h
+++ b/libc/include/arpa/ftp.h
@@ -34,6 +34,8 @@
 #ifndef _ARPA_FTP_H_
 #define	_ARPA_FTP_H_
 
+#include <sys/cdefs.h>
+
 /* Definitions for FTP; see RFC-765. */
 
 /*