It's a port of metalua (https://github.com/fab13n/metalua), a macro + syntax extension system for Lua. Given that CS's grammar is more exuberant than Lua's, the parser combinator library that supports runtime syntax extension requires much more work.
> lisp-2-ness is the thing I most despise about CL
It's conceptually ugly, but that's what makes non-hygienic macros usable.
A macro which uses a global variable is broken when used in a context which shadows this variable; if functions are not "normal" globals, there is much less chances that you'll shadow them accidentally.