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.
(1) the if_prom code needs to be cleaned up quite a bit
(right now it hard-codes client's ethernet address), and
(2) much of this code (esp: getsecs.c, netboot.c, newvers.sh,
rpcc.S) should be shared with other Alpha boot blocks,
and dev_net.[ch] should maybe go in libsa proper.