* Set stuff mostly in the environment, not on make(1)'s command line.
This is needed for MACHINE and MACHINE_ARCH (noted by bjh21), and keeps
the mk.conf-overriding-env behavior (suggested by several people).
* Use MAKEFLAGS to make the wrapper script more readable.
* When prepping objdir in tools for the default TOOLDIR value, just make
that objdir; leave the recursive "make obj" for later.