MFC rev. 265926:
(NANO_CONFIG): New variable containing path of config file, so that
the configuration can reference additional files relative to its own
location.

(NANO_MODULES): If set to "default", install all built modules.

Reviewed by:	imp
MFC r266195:

Remove some prototypes for undefined functions.
MFC r265465:

Don't reply monlist request when it's not enabled.
Document r266279 and r266280, '-J' flag to ps(1), and
corresponding top(1) change.

Sponsored by:	The FreeBSD Foundation