Change to kernel+modules build approach

[M. Warner Losh]

In message: <3F3C6D22.8050305 at freebsd.org>
            Scott Long <scottl at freebsd.org> writes:
: I can tell you first hand that this is painful.  However, in the case of
: PAE, it's somewhat neccessary since certain fundamental types change
: size.  I can envision solutions for this, but I'm not sure if they are
: less painful than just dealing with multiple module builds.

Personally I think that pae should be its own port, much like pc98 is
its own port, although much smaller in scope.  It has a few,
fundamental differences from the "stock" i386 port.  Since the data
type sizes are different with PAE there's no way around that.

Warner