Update to kernel headers v4.12.3.

Test: Built angler.
Change-Id: Icbcf4fac2334de8409b049ed7a3b4c24b4e98ce9
diff --git a/libc/kernel/uapi/linux/ip6_tunnel.h b/libc/kernel/uapi/linux/ip6_tunnel.h
index c3564f3..b7df956 100644
--- a/libc/kernel/uapi/linux/ip6_tunnel.h
+++ b/libc/kernel/uapi/linux/ip6_tunnel.h
@@ -19,6 +19,8 @@
 #ifndef _IP6_TUNNEL_H
 #define _IP6_TUNNEL_H
 #include <linux/types.h>
+#include <linux/if.h>
+#include <linux/in6.h>
 #define IPV6_TLV_TNL_ENCAP_LIMIT 4
 #define IPV6_DEFAULT_TNL_ENCAP_LIMIT 4
 #define IP6_TNL_F_IGN_ENCAP_LIMIT 0x1