diff --git a/port/external/enet.c b/port/external/enet.c
index 0bba1b919..7d03056d8 100644
--- a/port/external/enet.c
+++ b/port/external/enet.c
@@ -1,3 +1,10 @@
+#ifndef _WIN32
+#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#endif
+#endif
+
 #define ENET_IMPLEMENTATION 1
 #define ENET_NO_PRAGMA_LINK 1
+
 #include "external/enet.h"