move some parts of TTY_PERM_INVENT into core

This starts the tty perm_invent just in time later in the
startup rather than initializing it with the other
game windows.

This also splits the duties:

The core will inquire from the window port about how many
inventory slots it can fill.

The core will handle figuring out the inventory text and
inventory letters, and will do the traversing of internal
data structures like obj chains, and passing customization
options on to the window port.

The window port will look after placing each inventory slot's
text at an appropriate location on the screen.

This, in theory, makes the core-portion available for
window ports other than tty to use, though none currently do.
The decision of what goes in an inventory slot is all left up
to the core with the update_invent_slot interface.

Documentation updates will come later, not at this time.

include/wintype.h

@@ -111,6 +111,8 @@ typedef struct gi {
 #define NHW_MAP 3
 #define NHW_MENU 4
 #define NHW_TEXT 5
+#define NHW_PERMINVENT 6
+#define NHW_LAST_TYPE NHW_PERMINVENT
 
 /* attribute types for putstr; the same as the ANSI value, for convenience */
 #define ATR_NONE       0
@@ -162,19 +164,37 @@ typedef struct gi {
 
 #define MENU_BEHAVE_STANDARD      0x0000000U
 
+/* inventory modes */
+enum inv_modes { InvNormal = 0, InvShowGold = 1, InvSparse = 2, InvInUse = 4 };
+
+enum to_core_flags {
+    active           = 0x001,
+    prohibited       = 0x002,
+    no_init_done     = 0x004
+};
+
+enum from_core_requests {
+    request_settings = 1,
+    update_slot      = 2,
+    render           = 3
+};
+
 struct to_core {
+    long tocore_flags;
     boolean active;
     boolean use_update_inventory;    /* disable the newer slot interface */
-    int slotcount;
-    int low_slot_num, high_slot_num;
-    int max_slot_text;
+    int maxslot;
+    int needrows, needcols;
+    int haverows, havecols;
 };
 
 struct from_core {
-    long piflags;
-    int slot;           /* which inventory slot; 0 means info exchange only */
+    enum from_core_requests core_request;
+    enum inv_modes invmode;
+    boolean force_redraw;
+    int slot;           /* which inventory slot; 0 indicates request */
     int invlet;
-    const char *text;   /* the text to display */
+    char text[BUFSZ];
 };
 
 struct perminvent_info_t {
@@ -184,6 +204,8 @@ struct perminvent_info_t {
 
 typedef struct perminvent_info_t perminvent_info;
 
+#define CORE_INVENT
+
 /* clang-format on */
 
 #endif /* WINTYPE_H */