provides the correct functions for primary, secondary, and unified
boot blocks. actually behave correctly (e.g. expect correct arguments,
perform correct operations) depending on which you are. also
some minor cleanup.
machines with old firmware which doesn't pass it in the boot device
can work. Assume that if the ethernet address isn't passed in, it
uses the old (dain-bramaged) 'read' interface works on my 3000/300LX.
(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.
thorpej