How to let macros work without defining what a macro is...

[Bill Rozas <JINX%MIT-OZ@MIT-MC.ARPA>]

	This assumes that all macros work at the s-expression level,
which is not true in our implementation.  The only way to provide both
(especially syntax-expand) in all cases would be to fully reduce to
s-code and then invert to s-expressions.  This would imply full
(recursive) expansion always.

	In our system macros translate from s-expressions to s-code.
There are a few utilities, however, to emulate s-expression level
macros built on top of this.  But macros like COND, LET, etc are never
translated at the s-expression level.