That means `slist' is
((?\( . ".") (?\) . ".") (?$ . "\""))
In GNU Emacs at the same point of code execution, the value
of `slist' is
((40 . ".") (41 . ".") (36 . "\""))
Also, the numeric character values are already present in
`font-lock-defaults'.
Thanks! Your debugging info was extremely clear and allowed me to pinpoint
the problem (at least, I'm pretty sure ...); attached is a new version.