check options argument to wait{3,4,pid}(); from Klaus Klein in PR 3182.
fix typos; from Erik Bertelsen in PR port-i386/2272.
eliminate obsolete t_min and t_time shortcuts; from Bill Studenmund in
  PR kern/2440.
move inclusion of <sys/cdefs.h> up to catch all uses of __P();
  PR kern/2712.
Snapshot of new ARP code.

Our old ARP code was hardwired for 6-byte length medium
addresses, while the protocol is designed for any size.

This snapshot contains a first hack at getting rid of
Ethernet specific data structures. The ep driver is updated
(and tested on the PCI bus), the iy and fpa drivers have been
updated, but not real life tested yet.

If you want to test this with other drivers, you have to update
them first yourself, and probably tag the relevant directories.
Better contact me if you want to do this.
It's not necessary to initialize the `revents' field of struct pollfd.
Extinguish the link level address from struct arccom, too.
XXX Todo: change this in the hardware driver.
Oops, forgot some usages of ((struct arccom *)ifp)->ac_anaddr
Allocate and define AF_ARP and PF_ARP. These will be used to
a) communicate the hardware independent part of ARP packets (rfc826) from/to
if_*subr.c in the ongoing effort to rewrite the ARP subsystem for non-Ethernet
networks
b) communicate the hardware independent part of RARP packets (rfc903) from/to
userland sockets to avoid putting link level header format knowledge into
rarpd, when it is enhanced to support non-Ethernet networks.
- Add macros, to if_arp.h:struct arphdr, to access an ARP messages' variable
  fields based on the ar_hln and ar_pln fields.
- Add AR_ARP case to ether_output, using the ar_tha() macro defined above.
Changed arprequest() to use AF_ARP sockaddr and NOT build its own Ethernet
header. Added some missing pieces in ether_output() to support this.
Convert the arp receive/reply code to the new world order.
Fix obvious typo.
Initialize 'bestf' to make this compile again with -Wall.
allow includers to specify library-specific CPP flags via ${LIB}MISCCPPFLAGS
Correct low-order product code digits  for 3Com 3c597 family.
Prevent lota compiler warnings introduced with the -1.2C Makefile.
Changed in_revarpinput() to new ARP.
Converted revarprequest() to the new world order.
Having converted everything, remove the struct ether_arp definition completely.
Some small cleanup.
STILLTODO: some sanity checks of the (now) variable link level address length
in incoming packets..