diff --git a/src/wl_init.c b/src/wl_init.c
index 21a808aa..1ba497b7 100644
--- a/src/wl_init.c
+++ b/src/wl_init.c
@@ -26,7 +26,7 @@
 // It is fine to use C99 in this file because it will not be built with VS
 //========================================================================
 
-#define _POSIX_C_SOURCE 199309L
+#define _POSIX_C_SOURCE 200809L
 
 #include "internal.h"