diff --git a/tools/setup.lisp b/tools/setup.lisp
index 4094a2e5803a169f5716bdee3a551e4110516801..abdcebf5bacc292cbccb0d8a86d8ae5673915a3c 100644
--- a/tools/setup.lisp
+++ b/tools/setup.lisp
@@ -131,6 +131,10 @@
 (dolist (x '(sap-ref-8 sap-ref-16 sap-ref-32))
   (fmakunbound x))
 
+(in-package "C")
+(define-condition parse-unknown-type (condition)
+		  (specifier))
+
 (in-package "USER")
 
 ;;; Hack until real definition exists: