prototypes for the IPv6 ECN ingress/egress functions in sys/netinet/ip_ecn.h,
inside an #ifdef INET6 wrapper. So, wrap sys/netipsec ocurrences of
#include <netinet6/ip6_ecn.h>
in #ifdef __FreeBSD__/#endif, until both camps can agree on this
teensy little piece of namespace. Affects:
ipsec_output.c xform_ah.c xform_esp.c xform_ipip.c