diff --git a/lisp/org-exp-blocks.el b/lisp/org-exp-blocks.el
index 062e0622d..df41c4014 100644
--- a/lisp/org-exp-blocks.el
+++ b/lisp/org-exp-blocks.el
@@ -76,6 +76,8 @@
   (require 'cl))
 (require 'org)
 
+(defvar backend) ; dynamically scoped from caller
+
 (defvar org-exp-blocks-block-regexp
   (concat
    "^\\([ \t]*\\)#\\+begin_\\(\\S-+\\)"