based on the device size.

that some targets send.

anywhere other than offset 0 within the EEPROM, so we have to put our
settings at 0x100 instead.

this can probably be optimised down quite a lot.

device.

Separated the mechanisms of non-volatile storage access and non-volatile
stored options.

a word length.

that don't provide the full flexibility of a bit-bashing interface.

Temporarily hacked rtl8139.c to use the new interface.

Added CHAP authentication

defined in vsprintf.h.  (This may change, since vsprintf.h is a
non-standard name, but for now it's the one to use.)

There should be no need to include vsprintf.h just for DBG() statements,
since include/compiler.h forces it in for a debug build anyway.