fix github issue #266 - timed clairvoyance

When the hero has random clairvoyance, the code used
| (moves % 15) == 0 && rn2(2) != 0
(where 'moves' is actually the turn number) to decide when it would
kick in and show a portion of the map.  If the hero was fast enough
to get an extra move when the turn value met the (moves % 15) == 0
condition then clairvoyance could happen twice (or more if poly'd)
on the same turn.

The changes (one new field, reordering a few others) in 'struct
context' invalidate existing 3.7.0-x save files.

Fixes #266

doc/fixes37.0

@@ -1,4 +1,4 @@
-$NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.22 $ $NHDT-Date: 1576288434 2019/12/14 01:53:54 $
+$NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.26 $ $NHDT-Date: 1577050214 2019/12/22 21:30:14 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -13,6 +13,7 @@ improvements to pronoun usage when hallucinating
 function calls made from mapglyph based on dungeon level are now called once
 	per level
 fix accessing mons[-1] when trying to gate in a non-valid demon
+fast hero could have random clairvoyance happen more than once on same turn
 
 
 Fixes to Pre-3.7.0 Problems that Were Exposed Via git Repository
@@ -56,7 +57,7 @@ Code Cleanup and Reorganization
 move majority of global variables into instance_globals struct g
 move zeroobj, zeromonst, zeroany into const_globals struct cg
 remove STATIC_DCL, STATIC_OVL, STATIC_VAR, STATIC_PTR
-old Qt moved from win/Qt to win/Qt3
+old Qt moved from win/Qt to win/Qt3 and files renamed to use qt3_ prefix
 more current Qt for Qt version 4 and 5 moved from win/Qt4 to win/Qt; qt4
 	moniker changed to qt_
 

include/context.h

@@ -1,4 +1,4 @@
-/* NetHack 3.6	context.h	$NHDT-Date: 1575775592 2019/12/08 03:26:32 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.35 $ */
+/* NetHack 3.6	context.h	$NHDT-Date: 1577050216 2019/12/22 21:30:16 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.36 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Michael Allison, 2006. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -111,14 +111,15 @@ struct context_info {
     unsigned run;           /* 0: h (etc), 1: H (etc), 2: fh (etc) */
                             /* 3: FH, 4: ff+, 5: ff-, 6: FF+, 7: FF- */
                             /* 8: travel */
-    unsigned startingpet_mid;
+    unsigned startingpet_mid; /* monster id number for initial pet */
-    int current_fruit; /* fruit->fid corresponding to g.pl_fruit[] */
+    int current_fruit;      /* fruit->fid corresponding to g.pl_fruit[] */
-    int warnlevel;
+    int mysteryforce;       /* adjusts how often "mysterious force" kicks in */
     int rndencode;          /* randomized escape sequence introducer */
-    int mysteryforce;
+    int warnlevel;          /* threshold (digit) to warn about unseen mons */
     long next_attrib_check; /* next attribute check */
-    long stethoscope_move;
+    long seer_turn;         /* when random clairvoyance will next kick in */
-    short stethoscope_movement;
+    long stethoscope_move;  /* when a stethoscope was last used */
+    short stethoscope_movement; /* to track multiple moves on same turn */
     boolean travel;  /* find way automatically to u.tx,u.ty */
     boolean travel1; /* first travel step */
     boolean forcefight;

include/patchlevel.h

@@ -1,4 +1,4 @@
-/* NetHack 3.7	patchlevel.h	$NHDT-Date: 1575775596 2019/12/08 03:26:36 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.136 $ */
+/* NetHack 3.7	patchlevel.h	$NHDT-Date: 1577050214 2019/12/22 21:30:14 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.141 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Michael Allison, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -14,7 +14,7 @@
  * Incrementing EDITLEVEL can be used to force invalidation of old bones
  * and save files.
  */
-#define EDITLEVEL 3
+#define EDITLEVEL 4
 
 #define COPYRIGHT_BANNER_A "NetHack, Copyright 1985-2019"
 #define COPYRIGHT_BANNER_B \

src/allmain.c

@@ -1,4 +1,4 @@
-/* NetHack 3.6	allmain.c	$NHDT-Date: 1555552624 2019/04/18 01:57:04 $  $NHDT-Branch: NetHack-3.6.2-beta01 $:$NHDT-Revision: 1.100 $ */
+/* NetHack 3.6	allmain.c	$NHDT-Date: 1577050218 2019/12/22 21:30:18 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.136 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -66,6 +66,10 @@ boolean resuming;
         g.context.rndencode = rnd(9000);
         set_wear((struct obj *) 0); /* for side-effects of starting gear */
         (void) pickup(1);      /* autopickup at initial location */
+        /* only matters if someday a character is able to start with
+           clairvoyance (wizard with cornuthaum perhaps?); without this,
+           first "random" occurrence would always kick in on turn 1 */
+        g.context.seer_turn = (long) rnd(30);
     }
     g.context.botlx = TRUE; /* for STATUS_HILITES */
     update_inventory(); /* for perm_invent */
@@ -336,9 +340,21 @@ boolean resuming;
 #endif
             if (g.context.bypasses)
                 clear_bypasses();
-            if ((u.uhave.amulet || Clairvoyant) && !In_endgame(&u.uz)
+            if (g.moves >= g.context.seer_turn) {
-                && !BClairvoyant && !(g.moves % 15) && !rn2(2))
+                if ((u.uhave.amulet || Clairvoyant) && !In_endgame(&u.uz)
-                do_vicinity_map((struct obj *) 0);
+                    && !BClairvoyant)
+                    do_vicinity_map((struct obj *) 0);
+                /* we maintain this counter even when clairvoyance isn't
+                   taking place; on average, go again 30 turns from now */
+                g.context.seer_turn = g.moves + (long) rn1(31, 15); /*15..45*/
+                /* [it used to be that on every 15th turn, there was a 50%
+                   chance of farsight, so it could happen as often as every
+                   15 turns or theoretically never happen at all; but when
+                   a fast hero got multiple moves on that 15th turn, it
+                   could actually happen more than once on the same turn!] */
+            }
+            /* [fast hero who gets multiple moves per turn ends up sinking
+               multiple times per turn; is that what we really want?] */
             if (u.utrap && u.utraptype == TT_LAVA)
                 sink_into_lava();
             /* when/if hero escapes from lava, he can't just stay there */