Add petless conduct

Breaks saves.

src/dog.c

@@ -59,6 +59,7 @@ initedog(struct monst *mtmp)
     EDOG(mtmp)->revivals = 0;
     EDOG(mtmp)->mhpmax_penalty = 0;
     EDOG(mtmp)->killed_by_u = 0;
+    u.uconduct.pets++;
 }
 
 static int
@@ -152,6 +153,7 @@ make_familiar(struct obj *otmp, coordxy x, coordxy y, boolean quietly)
         /* 0,1,2:  b=80%,10,10; nc=10%,80,10; c=10%,10,80 */
         if (chance > 0) {
             mtmp->mtame = 0;   /* not tame after all */
+            u.uconduct.pets--; /* doesn't count as creating a pet */
             if (chance == 2) { /* hostile (cursed figurine) */
                 if (!quietly)
                     You("get a bad feeling about this.");

src/insight.c

@@ -2047,6 +2047,9 @@ show_conduct(int final)
         you_have_X(buf);
     }
 
+    if (!u.uconduct.pets)
+        you_have_never("had a pet");
+
     ngenocided = num_genocides();
     if (ngenocided == 0) {
         you_have_never("genocided any monsters");

src/minion.c

@@ -520,7 +520,17 @@ gain_guardian_angel(void)
              * [Note: this predates mon->mextra which allows a monster
              * to have both emin and edog at the same time.]
              */
-            mtmp->mtame = 10;
+            /* Too nasty for the game to unexpectedly break petless conduct on
+             * the final level of the game. The angel will still appear, but
+             * won't be tamed. */
+            if (u.uconduct.pets) {
+                /* guardian angel -- the one case mtame doesn't
+                 * imply an edog structure, so we don't want to
+                 * call tamedog().
+                 */
+                mtmp->mtame = 10;
+                u.uconduct.pets++;
+            }
             /* for 'hilite_pet'; after making tame, before next message */
             newsym(mtmp->mx, mtmp->my);
             if (!Blind)

src/topten.c

@@ -439,6 +439,8 @@ encodeconduct(void)
        entered-sokoban bit in the 'achieve' field */
     if (!u.uconduct.sokocheat && sokoban_in_play())
         e |= 1L << 12;
+    if (!u.uconduct.pets)
+        e |= 1L << 13;
 
     return e;
 }
@@ -594,6 +596,7 @@ encode_extended_conducts(char *buf)
     add_achieveX(buf, "deaf",         u.uroleplay.deaf);
     add_achieveX(buf, "nudist",       u.uroleplay.nudist);
     add_achieveX(buf, "bonesless",    !flags.bones);
+    add_achieveX(buf, "petless",      !u.uconduct.pets);
 
     return buf;
 }