+;;; The pretty-printer needs to know about our special tokens
+(defvar *backq-tokens*
+ '(backq-comma backq-comma-at backq-comma-dot backq-list
+ backq-list* backq-append backq-nconc backq-cons backq-vector))
+
+;;; Since our backquote is installed on the host lisp, and since
+;;; developers make mistakes with backquotes and commas too, let's
+;;; ensure that we can report errors rather than get an undefined
+;;; function condition on %READER-ERROR.
+#+sb-xc-host ; proper definition happens for the target
+(defun %reader-error (stream format-string &rest format-args)
+ (bug "READER-ERROR on stream ~S: ~?" stream format-string format-args))
+