diff --git a/io/lockf.c b/io/lockf.c
index aa5c673c8d..8ea83e15f0 100644
--- a/io/lockf.c
+++ b/io/lockf.c
@@ -15,6 +15,8 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <bits/types.h>
+
 #ifndef __OFF_T_MATCHES_OFF64_T
 
 #include <unistd.h>