patch 8.1.0062: popup menu broken if a callback changes the window layout

Problem:    Popup menu broken if a callback changes the window layout. (Qiming
            Zhao)
Solution:   Recompute the popup menu position if needed.  Redraw the ruler
            even when the popup menu is displayed.
diff --git a/src/proto/popupmnu.pro b/src/proto/popupmnu.pro
index d5e1bbd..f553100 100644
--- a/src/proto/popupmnu.pro
+++ b/src/proto/popupmnu.pro
@@ -4,6 +4,7 @@
 void pum_undisplay(void);
 void pum_clear(void);
 int pum_visible(void);
+void pum_may_redraw(void);
 int pum_get_height(void);
 int split_message(char_u *mesg, pumitem_T **array);
 void ui_remove_balloon(void);