DEFVST lossage

[RWK at MIT-MC (Robert W. Kerns)]

I haven't thought this out, but there exists a problem aproximately as
follows:

If you load a compiled DEFVST, without EXTEND being loaded, then do
(CONS-A-FOO), it loads EXTEND and lots of other guys, then barfs that
NIL isn't a class.  It got the NIL from the STRUCT=INFO-CLSS slot of
the STRUCT=INFO structure.  Perhaps the right thing to do at this juncture
is to create the class?  I don't know.