patch 9.1.0678: [security]: use-after-free in alist_add()

Problem:  [security]: use-after-free in alist_add()
          (SuyueGuo)
Solution: Lock the current window, so that the reference to
          the argument list remains valid.

This fixes CVE-2024-43374

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/terminal.c b/src/terminal.c
index 1fc0ef9..f801960 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -3680,10 +3680,10 @@
 		if (is_aucmd_win(curwin))
 		    do_set_w_closing = TRUE;
 		if (do_set_w_closing)
-		    curwin->w_closing = TRUE;
+		    curwin->w_locked = TRUE;
 		do_bufdel(DOBUF_WIPE, (char_u *)"", 1, fnum, fnum, FALSE);
 		if (do_set_w_closing)
-		    curwin->w_closing = FALSE;
+		    curwin->w_locked = FALSE;
 		aucmd_restbuf(&aco);
 	    }
 #ifdef FEAT_PROP_POPUP