lockf in installworld -- not a good idea

[Warner Losh]

> For what its worth.... I'd go with just stopping support for -j in
> installworld, even if things are CPU bound.

installworld should *NEVER* be done -j.  Ever.  That wasn't part of
the installworld bargin when it was started.  There's no point to it
at all.  As such, any support to make it work should be removed with
extreme prejustice.  Why on earth would you want to do installworld
-j?

Warner