Saving grace

Once per game, if receiving a killing blow from above 90% HP,
allow the hero to survive with 1 HP.

doc/fixes3-7-0.txt

@@ -1115,6 +1115,7 @@ give feedback when some types of damage are avoided due to MC (aka negation)
 feedback if a named, shape-shifted vampire reverted to original shape rather
 	than dying when engulfed could say "Dracula turns into Dracula"
 adjust archeologist and valkyrie starting intrinsics
+once per game if receiving killing blow from near-full hp, leave 1 hp
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository

include/extern.h

@@ -987,6 +987,7 @@ extern int monster_nearby(void);
 extern void end_running(boolean);
 extern void nomul(int);
 extern void unmul(const char *);
+extern int saving_grace(int);
 extern void losehp(int, const char *, schar);
 extern int weight_cap(void);
 extern int inv_weight(void);

include/patchlevel.h

@@ -17,7 +17,7 @@
  * Incrementing EDITLEVEL can be used to force invalidation of old bones
  * and save files.
  */
-#define EDITLEVEL 75
+#define EDITLEVEL 76
 
 /*
  * Development status possibilities.

include/you.h

@@ -419,7 +419,7 @@ struct you {
     Bitfield(uinvulnerable, 1); /* you're invulnerable (praying) */
     Bitfield(uburied, 1);       /* you're buried */
     Bitfield(uedibility, 1);    /* blessed food detect; sense unsafe food */
-    /* 1 free bit! */
+    Bitfield(usaving_grace, 1); /* prevents death once */
 
     unsigned udg_cnt;           /* how long you have been demigod */
     struct u_event uevent;      /* certain events have happened */

src/hack.c

@@ -3711,6 +3711,19 @@ maybe_wail(void)
     }
 }
 
+/* once per game, if receiving a killing blow from above 90% HP,
+   allow the hero to survive with 1 HP */
+int
+saving_grace(int dmg)
+{
+    if (!u.usaving_grace && (u.uhp <= dmg)
+        && (u.uhp * 100 / u.uhpmax) > 90) {
+        dmg = u.uhp - 1;
+        u.usaving_grace = TRUE; /* used up */
+    }
+    return dmg;
+}
+
 void
 losehp(int n, const char *knam, schar k_format)
 {
@@ -3734,6 +3747,7 @@ losehp(int n, const char *knam, schar k_format)
         return;
     }
 
+    n = saving_grace(n);
     u.uhp -= n;
     if (u.uhp > u.uhpmax)
         u.uhpmax = u.uhp; /* perhaps n was negative */

src/mhitu.c

@@ -1753,6 +1753,7 @@ mdamageu(struct monst *mtmp, int n)
         if (u.mh < 1)
             rehumanize();
     } else {
+        n = saving_grace(n);
         u.uhp -= n;
         if (u.uhp < 1)
             done_in_by(mtmp, DIED);