collapseos/blk/260

Cross compilation program

This programs allows cross compilation of boot binary and
icore. Run "262 LOAD" right before your cross compilation and
then set XCURRENT to CURRENT and XCOFF to H@.

This redefines defining words to achieve cross compilation.
The goal is two-fold:

1. Add an offset to all word references in definitions.
2. Don't shadow important words we need right now.

Words overrides like ":", "IMMEDIATE" and "CODE" are not
automatically shadowed to allow the harmless inclusion of
this unit. This shadowing has to take place in your xcomp
configuration.                                          (cont.)