First cut of doing 32-bit C code in the core

First cut of doing 32-bit C code in the core

A very preliminary implementation of 32-bit C code in the core.  This
currently breaks ADV, because the installer assumes the ADV is the
last two sectors in extlinux.sys -- need to figure out a way to deal
with this hopefully without breaking the migration protocol.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>