transition away from uIP.

Prepared ipv4.c for transition away from uIP.

Kill off the static single net device and move to proper dynamic
registration (which we need with the new device model).

Break the (flawed) assumption that all network-layer protocols can use
ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP
protocol using ARP_NET_PROTOCOL() and provide a single method for checking
the existence of a local network-layer address.

period before updating to the new driver API (which can cope with
having TX packets in progress).

(This actually matters once you try using TCP, because you *will*
receive full-sized frames.)

Shrink to 4kB for now.  We might want to see if it can be made
genuinely indicative of the RX ring size in the new TCP
implementation.

Update rtl8139 driver to instantiate an SPI interface with a three-wire
device attached.

(since SPI bit-bashing will require different delay semantics).

--nulltrap to the make target at the moment.)

as a result of our memory map editing, so strip out any empty regions.

Allow our functions to return a non-zero, non-error status (since the
INT 13 Extensions Check has to return the API version in the register
that is otherwise always used for the error code).

Report a non-zero API version from the INT 13 Extensions Check; GRUB
now uses extended reads.

library use later on
- some small mods to existing functions

being noticed...

flow of control through this code.

We now always add PCI and PnP headers even for ISA ROMs; there's no harm
in doing so.

UNDI loader is still missing.

on the stack.

the jmp instruction).

Print warning message at probe time.

not-yet-updated drivers to at least function.

AoE now uses the retry timer mechanism.

layer asynchronous, so keeping the sync/async boundary within aoedev.c
seems cleanest for now.

point trying to use the old boot sequence.  Replaced with a call to the
AoE demo code, so that people can at least build and try something useful.