CASE using other equality predicates

[David.Dill@A.CS.CMU.EDU (C410DD60)]

While the proposed change might be useful for other reasons, there are a
variety of other solutions to this particular problem.  The most obvious
is to call the reader to read the user commands with *package* bound to
the commandpackage package (either explicitly or using IN-PACKAGE), so
that the user commands are interned in the same place as the code.

What I do when I want to be extra careful is put all the commands in
a completely separate package with NO other symbols, export the commands
from that package, explicitly qualify all the commands when I use them
in code (in this example, in the case clauses), and read the symbols
typed by the user into the special command name package.