I've made a minor change to the top-level makefile and
share/mk/bsd.own.mk. 

The new variable MKOBJDIRS, which defaults to "no", determines whether
a "make obj" gets invoked during a "make build"; if it's not set to
"no", a "make obj" is invoked after the "make cleandir".  It's done
after, rather than before, so that transitions from non-objdir-based
builds to objdir-based builds are more likely to work.

If you set MKOBJDIRS=yes in your /etc/mk.conf, "make build" should
populate obj directories as appropriate.

					- Bill