Log Message:
Apply various features and fixes from NetBSD basesrc:
* Implement options:
	expandtab
	gtagsmode
	matchchars
* Fix tty garbling when quitting from recovery mode.
* Don't coredump during autoindent edge case.
* Set internal version to "nvi-1.81.6nb4 (2009-08-07)"
* Crank pkgrevision to nb4.