Issue: STACK-LET (Version 1)

[jrose@Sun.COM (John Rose)]

 ...
       It is always permissible for STACK-LET to behave like LET.
       Its use is merely advice to an implementation about the use
       of a variable which might not otherwise be provable.
 ...
  It would also be possible to unify this proposal with
  REST-ARGUMENT-EXTENT. The technique would be to allow
   (LET ((X (LIST ...)))
     (DECLARE (DYNAMIC-EXTENT X))
     ...)
  to be rewritten by the compiler as:
   (SYSTEM::STACK-LET ((X (LIST ...)))
     ...)
  for example.

The DYNAMIC-EXTENT declaration is a smaller, cleaner addition
than a new STACK-LET special form.

It's less of a burden on implementors and users to ignore a declaration
than to expand one special form into another.

				-- John