diff --git a/src/globals.h b/src/globals.h
index 5e6b646..b6541a4 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1311,6 +1311,7 @@
 #ifdef MSWIN
 EXTERN char_u	toupper_tab[256];	// table for toupper()
 EXTERN char_u	tolower_tab[256];	// table for tolower()
+EXTERN int	found_register_arg INIT(= FALSE);
 #endif
 
 #ifdef FEAT_LINEBREAK