--- common/game.h.orig	Wed Aug 16 22:18:15 2000
+++ common/game.h	Wed Aug 16 22:19:12 2000
@@ -113,7 +113,7 @@
   int fogofwar;
   int fogofwar_old;	/* as the fog_of_war bit get changed by setting
 			   the server we need to remember the old setting */
-
+  int killstack;
   int num_unit_types;
   int num_tech_types;  /* including A_NONE */
 
@@ -258,6 +258,10 @@
 #define GAME_DEFAULT_FOGOFWAR        1
 #define GAME_MIN_FOGOFWAR            0
 #define GAME_MAX_FOGOFWAR            1
+
+#define GAME_DEFAULT_KILLSTACK 1
+#define GAME_MIN_KILLSTACK     0
+#define GAME_MAX_KILLSTACK     1
 
 #define GAME_DEFAULT_DIPLCHANCE      80
 #define GAME_MIN_DIPLCHANCE          1
--- common/game.c.orig	Wed Aug 16 22:20:41 2000
+++ common/game.c	Wed Aug 16 22:21:39 2000
@@ -757,6 +757,7 @@
   game.spacerace   = GAME_DEFAULT_SPACERACE;
   game.fogofwar    = GAME_DEFAULT_FOGOFWAR;
   game.fogofwar_old= game.fogofwar;
+  game.killstack = GAME_DEFAULT_KILLSTACK;
   game.auto_ai_toggle = GAME_DEFAULT_AUTO_AI_TOGGLE;
   game.barbarianrate  = GAME_DEFAULT_BARBARIANRATE;
   game.onsetbarbarian = GAME_DEFAULT_ONSETBARBARIAN;
--- server/unitfunc.c.orig	Wed Aug 16 22:25:18 2000
+++ server/unitfunc.c	Wed Aug 16 22:34:18 2000
@@ -2879,7 +2879,7 @@
   if( (incity) ||
       (map_get_special(punit->x, punit->y)&S_FORTRESS) ||
       (map_get_special(punit->x, punit->y)&S_AIRBASE) ||
-      unitcount == 1) {
+      unitcount == 1 || !game.killstack) {
     notify_player_ex(pplayer, punit->x, punit->y, E_UNIT_LOST,
 		     _("Game: You lost a%s %s under an attack from %s's %s%s."),
 		     n_if_vowel(get_unit_type(punit->type)->name[0]),
--- server/stdinhand.c.orig	Wed Aug 16 22:07:11 2000
+++ server/stdinhand.c	Wed Aug 16 22:16:30 2000
@@ -536,7 +536,14 @@
     N_("If this is set to 1, only those units and cities within the sightrange "
        "of your own units and cities will be revealed to you. You will not see "
        "new cities or terrain changes in squares not observed.") },
-
+  { "killstack", &game.killstack,
+    SSET_RULES_FLEXIBLE, SSET_TO_CLIENT,
+    GAME_MIN_KILLSTACK, GAME_MAX_KILLSTACK, GAME_DEFAULT_KILLSTACK,
+    N_("Whether to enable kill units stack"),
+    N_("If this is set to 1, all units in the same tile of a killed unit will"
+       " be killed (unless they are on a fortress, airbase or city); this is the"
+       " default. If this options is set to 0, units are killed one by one,"
+       " except by nuclear weapons, of course.") },
   { "diplchance", &game.diplchance,
     SSET_RULES_FLEXIBLE, SSET_TO_CLIENT,
     GAME_MIN_DIPLCHANCE, GAME_MAX_DIPLCHANCE, GAME_DEFAULT_DIPLCHANCE,