zebra: Add support for ZEBRA_NEXTHOP_IPV4_IFINDEX

Actually implement the IPV4_IFINDEX nexthop type that has been drifting
around as a definition forever (without any warning about it being a
placeholder).

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
1 file changed