local declarations

[RMS at MIT-AI (Richard M. Stallman)]

A local declaration around an entire function definition can
now be written with a DECLARE as the first object in the body.
If there are both a declaration and a documentation string,
they can appear in either order (if anything checks for documentation
strings in interpreted functions, it needs to be fixed to do this).

Such local declarations work even in interpreted code.  This doesn't
matter for SPECIAL declarations but it could potentially matter for
other kinds.

A new local declaration (RETURN-LIST names) exists.  It specifies
names (as documentation only) for the values returned by a function.
This list will be the second value returned by ARGLIST.