more PR #892 - strength lose due to poison

Refine pull request #802 by entrez.  Applying damage within a loop
could potentially damage the hero multiple times, maybe using up
an amulet of life saving and then killing hero anyway, or causing
rehumanization and taking further HP from normal form, or both,
causing rehumanization and then using up amulet of life saving.

Accumulate the damage in the loop and then apply it as a unit.

src/attrib.c

@@ -192,6 +192,7 @@ adjattrib(
     return TRUE;
 }
 
+/* strength gain */
 void
 gainstr(struct obj *otmp, int incr, boolean givemsg)
 {
@@ -209,30 +210,35 @@ gainstr(struct obj *otmp, int incr, boolean givemsg)
                      givemsg ? -1 : 1);
 }
 
-/* may kill you; cause may be poison or monster like 'a' */
+/* strength loss, may kill you; cause may be poison or monster like 'a' */
 void
 losestr(int num, const char *knam, schar k_format)
 {
     int uhpmin = minuhpmax(1), olduhpmax = u.uhpmax;
-    int ustr = ABASE(A_STR) - num;
+    int ustr = ABASE(A_STR) - num, amt, dmg;
-
-    /* in case HP loss kills the hero once Str hits the minimum */
-    if (!knam || !*knam) {
-        knam = "terminal frailty";
-        k_format = KILLED_BY;
-    }
 
+    dmg = 0;
     while (ustr < ATTRMIN(A_STR)) {
         ++ustr;
         --num;
-        losehp(6, knam, k_format);
+        amt = rn1(4, 3); /* (0..(4-1))+3 => 3..6; used to use flat 6 here */
+        dmg += amt;
         if (Upolyd) {
-            u.mhmax -= 6;
+            u.mhmax -= min(amt, u.mhmax - 1);
         } else {
-            setuhpmax(u.uhpmax - 6);
+            setuhpmax(u.uhpmax - amt);
         }
         g.context.botl = TRUE;
     }
+    if (dmg) {
+        /* in case damage is fatal and caller didn't supply killer reason */
+        if (!knam || !*knam) {
+            knam = "terminal frailty";
+            k_format = KILLED_BY;
+        }
+        losehp(dmg, knam, k_format);
+    }
+
     if (u.uhpmax < uhpmin) {
         setuhpmax(min(olduhpmax, uhpmin));
         if (!Drain_resistance)