* define NOfoo before .including <bsd.own.mk> or anything else that
might (indirectly) .include it, not after.
* defining MKfoo=no isn't what Makefiles are supposed to do
(yes, both mistakes were present :)
XXX docs are left out for the moment
the recover script is also left out, but provided by the older vi
The src/usr.bin/nvi directory is not descended into yet, but is otherwise
functional
apb