+ (:arg-types character
+ ;; KLUDGE: having a SATISFIES type here is too hairy for
+ ;; the cross-compiler (running on an arbitrary CL host)
+ ;; to cope with. Since we know we only have standard
+ ;; characters in the build anyway, we can restrict the
+ ;; cross-compiler's arg type to standard char, and all
+ ;; is well.
+ #+sb-xc-host
+ (:constant standard-char)
+ #-sb-xc-host
+ (:constant (satisfies inlinable-character-constant-p)))