diff --git a/common/loop.c b/common/loop.c
index 1b174967..750bee75 100644
--- a/common/loop.c
+++ b/common/loop.c
@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 199309L
 #include <limits.h>
 #include <string.h>
 #include <stdbool.h>