ensure that we only drop our self-reference exactly once.

To maintain the guarantee that an object won't go out of scope
unexpectedly while one of its event handlers is being called, the
event-calling functions now automatically obtain and drop extra
references.

functions.

Add "xfer" to all xfer functions and "job" to all job functions.

the most generally useful way.

in code defining reference-counted objects.

Dehyphenate "data-transfer".

functions.

output buffering defintions and the like)

ISA 3c509 is currently non-functional, although the EISA (3c509-eisa) and
MCA (3c529) variants should build OK.

None of this code is yet tested.

up in the same colour as debug messages for the application stream.

DBG_AC_IF(), to avoid namespace collisions.

Make expand_buffer() a non-inline function, so that we can add debug
messages.

Expandable buffers now don't *always* round up to the next power of two.
This allows e.g. loading a 137MB ISO image on a machine with only 256MB
RAM...

optimise these down to the correct single "roll"/"rorl" instruction.

more easily within gPXE.

Note that we don't have function bodies for these functions yet.

correct prototypes for srandom(), rand() and srand().