patch 8.2.4619: mapping is cancelled when mouse moves and popup is visible

Problem:    Mapping is cancelled when mouse moves and popup is visible.
Solution:   Only generate mouse moved events when a popup may use them.
            (closes #10004)
diff --git a/src/globals.h b/src/globals.h
index 1a50649..cd8893b 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -736,6 +736,9 @@
 // Set to TRUE if there is any visible popup window.
 EXTERN int	popup_visible INIT(= FALSE);
 
+// Set to TRUE if a visible popup window may use a MOUSE_MOVE event
+EXTERN int	popup_uses_mouse_move INIT(= FALSE);
+
 EXTERN int	text_prop_frozen INIT(= 0);
 #endif