I just figured out something: it works if I use the source-only
(cl-dbus) version of the package.  What's broken is the sbcl-dbus (and I
assume ecl-dbus).  But that's not big deal, in fact it's perfectly fine
to ship the source-only version of a single library, it blends in with
the rest since all(?) Common Lisp compilers compile on demand.

-- 
Pierre Neidhardt
https://ambrevar.xyz/