Somewhat replaces some earlier work done by hg/lg, but much more
complete, so we kept it as is, because it's bringing in even more parts
after this.
Reviewed-by: Karl Palsson <karlp@tweak.net.au>
Applies to both, and clearly shows that cmu.h needs to be extracted as
common code.
Originally from: e31d312331
and checked in the HG/LG reference manuals.
