patch 7.4.1557
Problem:    Windows cannot be identified.
Solution:   Add a unique window number to each window and functions to use it.
diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index f5e0d19..7035f26 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -59,6 +59,7 @@
 int list_append_tv(list_T *l, typval_T *tv);
 int list_append_dict(list_T *list, dict_T *dict);
 int list_append_string(list_T *l, char_u *str, int len);
+int list_append_number(list_T *l, varnumber_T n);
 int list_insert_tv(list_T *l, typval_T *tv, listitem_T *item);
 void list_insert(list_T *l, listitem_T *ni, listitem_T *item);
 void vimlist_remove(list_T *l, listitem_T *item, listitem_T *item2);
diff --git a/src/proto/window.pro b/src/proto/window.pro
index 613fe21..3c511e3 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -83,4 +83,8 @@
 matchitem_T *get_match(win_T *wp, int id);
 int get_win_number(win_T *wp, win_T *first_win);
 int get_tab_number(tabpage_T *tp);
+int win_getid(typval_T *argvars);
+int win_gotoid(typval_T *argvars);
+void win_id2tabwin(typval_T *argvars, list_T *list);
+int win_id2win(typval_T *argvars);
 /* vim: set ft=c : */