groundwork for an interface change

Add a new window-port interface function
     perminvent_info *
     update_invent_slot(winid window, int slot, perminvent_info *);

That should be nice and flexible and allow exchanges of useful
information between the core and the window port. Information
to be exchange can be easily modified in include/wintype.h as
things evolve.

Information useful to the core can be exchanged from the
window-port in struct to_core.

Information useful from the core to the window-port can be
passed in struct from_core.

I'm not going to update any docs until much later after things
are fully working and settled.

This also doesn't fix or have anything to do with existing
TTY_PERM_INVENT issues.

win/share/safeproc.c

@@ -74,7 +74,7 @@ struct window_procs safe_procs = {
     safe_create_nhwindow, safe_clear_nhwindow, safe_display_nhwindow,
     safe_destroy_nhwindow, safe_curs, safe_putstr, safe_putmixed,
     safe_display_file, safe_start_menu, safe_add_menu, safe_end_menu,
-    safe_select_menu, safe_message_menu, safe_update_inventory,
+    safe_select_menu, safe_message_menu,
     safe_mark_synch,
     safe_wait_synch,
 #ifdef CLIPPING
@@ -100,6 +100,8 @@ struct window_procs safe_procs = {
     safe_status_finish, safe_status_enablefield,
     safe_status_update,
     safe_can_suspend,
+    safe_update_inventory,
+    safe_update_invent_slot,
 };
 
 struct window_procs *
@@ -270,12 +272,6 @@ safe_message_menu(
     return '\033';
 }
 
-void
-safe_update_inventory(int arg UNUSED)
-{
-    return;
-}
-
 void
 safe_mark_synch(void)
 {
@@ -476,6 +472,23 @@ safe_status_update(
 {
 }
 
+void
+safe_update_inventory(int arg UNUSED)
+{
+    return;
+}
+
+perminvent_info *
+safe_update_invent_slot(
+    winid window,  /* window to use, must be of type NHW_MENU */
+    int inventory_slot,                 /* slot id: 0 - info return to core */
+                                        /*          1 - gold slot */
+                                        /*          2 - 29 obj slots */
+    perminvent_info *pi)
+{
+    return (perminvent_info *) 0;
+}
+
 /**************************************************************
  * These are some optionally selectable routines that add
  * some base functionality over the safe_* versions above.