diff --git a/libc/include/sys/auxv.h b/libc/include/sys/auxv.h
index 918442f..0d753c3 100644
--- a/libc/include/sys/auxv.h
+++ b/libc/include/sys/auxv.h
@@ -29,6 +29,7 @@
 #define _SYS_AUXV_H_
 
 #include <linux/auxvec.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS