updated window_procs

Add a non-string identifier to window_procs for use in runtime
identification of the current window port being used.

Use a macro WPID to add the identification at the top of the
various existing window_procs declarations. It expands to the
existing text string, as well as the newly added field wp_id
with a wp_ identifier.

For example, WPID(tty) expands to: "tty", wp_tty

The generated wp_tty must be present in the wp_ids enum at
the top of include/winprocs.h.

The WINDOWPORT(x) macro has been updated to expand to a simple
value comparison (port.wp_id == wp_x), instead of a
string comparison.

win/chain/wc_chainin.c

@@ -594,7 +594,7 @@ chainin_update_invent_slot(
 }
 
 struct window_procs chainin_procs = {
-    "-chainin", 0, /* wincap */
+    WPIDMINUS(chainin), 0, /* wincap */
     0,             /* wincap2 */
     {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* color availability */
     /*

win/chain/wc_chainout.c

@@ -717,7 +717,7 @@ chainout_update_invent_slot(
 }
 
 struct chain_procs chainout_procs = {
-    "-chainout", 0, /* wincap */
+    WPIDMINUS(chainout), 0, /* wincap */
     0,              /* wincap2 */
     {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* color availability */
     /*