user interface macros

[David Gray <gray@lucid.com>]

> To be specific, I think what you want to do about DEFCLASS is to define
> precisely how each of the standard options is passed through, and not to
> define at all whether and how nonstandard options are passed through,
> other than to mention that nonstandard options might be present and to
> discuss the naming restrictions (packages).

That would be sufficient for implementation-defined options, but
non-standard options should also include user-defined options.  In order
for the metaclass writer to be able to define new options, there needs to
be a standard correspondence between the DEFCLASS form and the arguments to
ENSURE-CLASS-USING-CLASS.