Index: dhcpcd-6.11.5/ipv6.c
===================================================================
--- dhcpcd-6.11.5.orig/ipv6.c	2016-12-21 06:37:39.844993205 -0500
+++ dhcpcd-6.11.5/ipv6.c	2016-12-21 06:37:39.840993204 -0500
@@ -50,6 +50,13 @@
 #  include <netinet6/nd6.h>
 #endif
 
+#ifdef __linux__
+/* Hack for older kernels. It should never trigger these branches */
+#ifndef IFA_F_DADFAILED
+#define IFA_F_DADFAILED
+#endif
+#endif
+
 #include <errno.h>
 #include <ifaddrs.h>
 #include <inttypes.h>