Update to kernel headers v4.12.3.

Test: Built angler.
Change-Id: Icbcf4fac2334de8409b049ed7a3b4c24b4e98ce9
diff --git a/libc/kernel/uapi/linux/seg6.h b/libc/kernel/uapi/linux/seg6.h
index 43a1c3b..6f7b8dd 100644
--- a/libc/kernel/uapi/linux/seg6.h
+++ b/libc/kernel/uapi/linux/seg6.h
@@ -18,6 +18,8 @@
  ****************************************************************************/
 #ifndef _UAPI_LINUX_SEG6_H
 #define _UAPI_LINUX_SEG6_H
+#include <linux/types.h>
+#include <linux/in6.h>
 struct ipv6_sr_hdr {
   __u8 nexthdr;
   __u8 hdrlen;