Declarations from macros

[MOON at SCRC-TENEX]

Kent's idea of having macros able to expand into declarations is probably
a good idea.  Places that look for declarations are probably all going to
expand macros eventually anyway.

Documentation strings should be treated the same as declarations.  It might even
be all right to replace "naked" documentation strings with declarations.

What about a macro that wants to expand into both a declaration and some code,
perhaps initializations of variables?  Or do such macros always take a body and
expand into a LET?