diff --git a/.sbclrc b/.sbclrc
index 6fafa286..7cd9cab0 100644
--- a/.sbclrc
+++ b/.sbclrc
@@ -36,14 +36,12 @@ The actual profiles are in the subsubdirectories.")
                                                (find-guix-library-dirs *guix-profiles-dir*))))
   "Call this to set `cffi:*foreign-library-directories*' to DIRS."
   (when (ignore-errors (asdf:load-system "cffi"))
-    (setf (symbol-value (find-symbol (string '*foreign-library-directories*)
-                                     (find-package 'cffi)))
-
-          (union (symbol-value (find-symbol (string '*foreign-library-directories*)
-                                            (find-package 'cffi)))
-                 ;; CFFI needs a trailing "/".
-                 (delete nil (mapcar #'uiop:ensure-directory-pathname dirs))
-                 :test #'uiop:pathname-equal))))
+    (let ((sym (read-from-string "cffi:*foreign-library-directories*")))
+      (setf (symbol-value sym)
+            (union (symbol-value sym)
+                   ;; CFFI needs a trailing "/".
+                   (delete nil (mapcar #'uiop:ensure-directory-pathname dirs))
+                   :test #'uiop:pathname-equal)))))
 
 ;; Set it by default.
 (set-cffi-library-dirs)