It would make life slightly easier and less confusing for Clozure users if this could be extended just slightly:
(defparameter *unicode*
#+(or sb-unicode unicode ics ccl) t
#-(or sb-unicode unicode ics ccl) nil)
Clozure supposedly only uses Unicode for characters, so it ought to be a fine assumption. I've gotten around this on a current project by placing these lines in my .asd file:
#+ccl
(push :unicode *features*)
The *features* variable seems to also include some other options if you'd rather (I don't know if any of these are deprecated or preferable, I'm a bit new to all this): :clozure, :clozure-common-lisp, :openmcl-unicode-strings.
Oh, and incidentally, thanks for this library! I haven't been so pleased with a database library for as long as I can remember. It's really a joy to use.