config(8) should check if a scheduler is selected

[Bruce Evans]

On Sat, 19 Apr 2003, Mike Barcroft wrote:

> Bruce Evans <bde at zeta.org.au> writes:
> > It is the only mandatory option (sic).  Kernels with no options (although
    [SCHED_4BSD/SCHED_ULE]
> > they might not be useful) can be built except for this bug.  Example of
>
> Since all `options' are optional, maybe `sched' should be its own
> directive with two possible values: `4BSD' or `ULE'.

This would only be a name change since you would still have to set it.
I want defaults for "standard" options like this with a way to override
them.  A defaults file could be included to get the defaults (after fixing
the bugs in the include directive).  Then it there should be a cleaner
way of overriding the options than this current way:

options 	SCHED_4BSD	# Default (from include file).
#nooptions 	SCHED_4BSD	# Have to know name of old opt to turn it off.
nooption 	SCHED_4BSD	# Actual spelling of directive is astonishing.
options 	SCHED_ULE	# Set new option.

Bruce