Saying M here will produce a module called ip6_gre. If unsure, say N.
+config IPV6_FOU
+ tristate
+ default NET_FOU && IPV6
+
+config IPV6_FOU_TUNNEL
+ tristate
+ default NET_FOU_IP_TUNNELS && IPV6_FOU
+ select IPV6_TUNNEL
+
config IPV6_MULTIPLE_TABLES
bool "IPv6: Multiple Routing Tables"
select FIB_RULES