above only; since this is the only occurence, fix it locally rather than in
<sys/cdefs.h> as to not remove all the functionality on pre-2.8 systems.
XXX Shouldn't use zero-length arrays at all.
Among other, add ARPHRD_ARCNET definition, make sure the hardware type is
set on outgoing ARP packets, make sure we dont send out replies as broadcasts.
Some of the stuff (e.g., rarpd, bootpd, dhcpd etc., libsa) still will
only support Ethernet. Tcpdump itself should be ok, but libpcap needs
lot of work.
For the detailed change history, look at the commit log entries for
the is-newarp branch.