diff --git a/src/tls.c b/src/tls.c
index 7ab4e1e1..94854658 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -11,6 +11,7 @@
 
 #include <time.h>
 #include <stdio.h>
+#include <fcntl.h>
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>