--- src/core/cfg.y.orig	Mon May 15 22:30:18 2017
+++ src/core/cfg.y	Mon May 15 22:30:40 2017
@@ -35,6 +35,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <arpa/inet.h>
 #include <string.h>
