adding support for Heimdal/KTH Kerberos where easy to do so. Eliminate
bsd.crypto.mk.
There is still a bunch more work to do, but crypto is now more-or-less
fully merged into the base NetBSD distribution.
determines which crypto set to build based on <bsd.crypto.mk> and invokes
the programs with the various correct options.
Not complete yet, but a good starting point for a few things, and a little
more flexible than the method used in the release: target in etc/Makefile.