patch 8.2.4609: :unhide does not check for failing to close a window

Problem:    :unhide does not check for failing to close a window.
Solution:   When closing a window fails continue with the next one.  Do not
            try closing the autocmd window. (closes #9984)
diff --git a/src/window.c b/src/window.c
index cf11acf..435ad03 100644
--- a/src/window.c
+++ b/src/window.c
@@ -43,7 +43,6 @@
 static int may_open_tabpage(void);
 static int win_enter_ext(win_T *wp, int flags);
 static void win_free(win_T *wp, tabpage_T *tp);
-static int win_unlisted(win_T *wp);
 static void win_append(win_T *after, win_T *wp);
 static void frame_append(frame_T *after, frame_T *frp);
 static void frame_insert(frame_T *before, frame_T *frp);
@@ -5233,7 +5232,7 @@
  * Return TRUE if "wp" is not in the list of windows: the autocmd window or a
  * popup window.
  */
-    static int
+    int
 win_unlisted(win_T *wp)
 {
     return wp == aucmd_win || WIN_IS_POPUP(wp);