Reported by Andrew Walrond <andrew@walrond.org>
Changeset c19e654ddb
("gre: Add netlink interface") added an include
of linux/ip.h to linux/if_tunnel.h
We can't really let that get exposed to userspace
because this conflicts with types defined in netinet/ip.h
which userland is almost certainly going to have included
either explicitly or implicitly.
So guard this include with a __KERNEL__ ifdef.
Signed-off-by: David S. Miller <davem@davemloft.net>