Fix osc.el compilation warning

* lisp/osc.el (compilation-filter-start): Avoid compilation warning.

diff --git a/lisp/osc.el b/lisp/osc.el
index 89467bc4cfbd983d2d26912bb83323cbf857ba13..ea6abaebd3b2f96cdb2b3d53b2d416ae31602763 100644 (file)
--- a/lisp/osc.el
+++ b/lisp/osc.el
@@ -171,6 +171,8 @@ must be in `compilation-filter-hook'."
   :group 'osc
   :version "29.0")
 
+(defvar compilation-filter-start)
+
 ;;;###autoload
 (defun osc-compilation-filter ()
   "Maybe collect OSC control sequences.