diff --git a/include/lib/libc/aarch64/time_.h b/include/lib/libc/aarch64/time_.h
index cbc34e7..68ab1b8 100644
--- a/include/lib/libc/aarch64/time_.h
+++ b/include/lib/libc/aarch64/time_.h
@@ -4,9 +4,14 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#ifndef TIME__H
+#define TIME__H
+
 #ifndef SIZET_
 typedef unsigned long size_t;
 #define SIZET_
 #endif
 
 typedef long int time_t;
+
+#endif /* TIME__H */