separate xfer method.

Add missing .alloc_iob entries to several xfer_interface_operations
structures.

implemented smbios_get_uuid().

No Microsoft intellectual property was harmed in the production of
this code.

executing any image, not just a script.  (This will enable pxelinux to
use relative URIs, should it wish to.)

wasn't meant for my local "master" branch ;)
This reverts commit 373022108b.

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

Experimentation reveals that gcc ignores -mrtd for the implicit
arithmetic functions (e.g. __udivdi3), but not for the implicit
memcpy() and memset() functions.  Mark the implicit arithmetic
functions with __attribute__((cdecl)) to compensate for this.

(Note: we cannot mark with with __cdecl, because we define __cdecl to
incorporate regparm(0) as well.)

This reverts commit ed06bd8a89.

Kill off use of etherboot.h outside drivers/net.

which respond to close with a reopen() (e.g. iSCSI).

xfer_window() function, which can return a scalar rather than a
boolean.