diff --git a/common/include/editor/kdefs.h b/common/include/editor/kdefs.h
index a1de0a068..1153b5157 100644
--- a/common/include/editor/kdefs.h
+++ b/common/include/editor/kdefs.h
@@ -11,6 +11,8 @@ AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
 COPYRIGHT 1993-1999 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
 */
 
+#pragma once
+
 #ifdef __cplusplus
 extern "C" {
 #endif