equal? Bug in PC Scheme

[Guenther Goerz <goerz@rz.informatik.uni-hamburg.dbp.de>]

There seems to be a bug in PC Scheme's (ver. 3.03) EQUAL?: If you ask
whether the empty vector equals the empty vector, it says false.
 
 (equal? #() #())  =>  ()
 
Vector is the only datatype where this happens.
 
---Guenther