Changed processing of configuration files.

Changed processing of configuration files.

run/cf is no longer a symlink to ../cf, I've replaced it by make
rules which generate the configuration files in run/cf by preprocessing
those in cf according to CONFIG_xxx switches in config.mk (in the same
way as we already do in mkdist).

I'd like to migrate many settings local to the Centrum configs to the
main CVS without having to update several separate copies of the config.

*** CAVEAT ***  After updating to this version, you need to either
make distclean or

	rm run/cf
	mkdir run/cf

manually _before_ running make, else could lose your config files.