The multiboot specification states that, for raw images, if
load_end_addr is zero then it should be interpreted as meaning "use
the entire file", and if bss_end_addr is zero it should be interpreted
as meaning "no bss".

Add yet another ugly hack to iscsiboot.c, this time to allow the user to
inhibit the shutdown/removal of the iSCSI INT13 device (and the network
devices, since they are required for the iSCSI device to function).

On the plus side, the fact that shutdown() now takes flags to
differentiate between shutdown-for-exit and shutdown-for-boot means that
another ugly hack (to allow returning via the PXE stack on BIOSes that
have broken INT 18 calls) will be easier.

I feel dirty.

otherwise.  :(

Some shuffling around of the image management code; this needs tidying up.

list.

Added FEATURE() macros to most relevant (non-driver) files.

bytes of useless zeroes in the final image.

pointer to it.

Shut down before jumping to the multiboot image.

if we don't.

address, to work around OS bugs.

userptr_add().

it if we don't.

refer to them by name from the command line, or build them into a
multiboot module list.

Use setting image->type to disambiguate between "not my image" and "bad
image"; this avoids relying on specific values of the error code.

information table yet).