Fix some of the NPC attacking logic

data/json/items/ammo.json

@@ -385,7 +385,7 @@
     "category": "spare_parts",
     "material": [ "stone" ],
     "ammo_type": "rock",
-    "flags": [ "TRADER_AVOID" ],
+    "flags": [ "TRADER_AVOID", "NPC_THROWN" ],
     "weight": "657 g",
     "volume": "250 ml",
     "bashing": 7,

src/npc.cpp

@@ -2672,6 +2672,11 @@ int npc::closest_enemy_to_friendly_distance() const
     return ai_cache.closest_enemy_to_friendly_distance();
 }
 
+const std::vector<weak_ptr_fast<Creature>> &npc::get_cached_friends() const
+{
+    return ai_cache.friends;
+}
+
 std::string npc_attitude_name( npc_attitude att )
 {
     switch( att ) {

src/npc.h

@@ -1270,6 +1270,7 @@ class npc : public player
 
         // accessors to ai_cache functions
         int closest_enemy_to_friendly_distance() const;
+        const std::vector<weak_ptr_fast<Creature>> &get_cached_friends() const;
 
     private:
         npc_attitude attitude = NPCATT_NULL; // What we want to do to the player
@@ -1292,6 +1293,11 @@ class npc : public player
         const std::shared_ptr<npc_attack> &get_current_attack() const {
             return ai_cache.current_attack;
         }
+
+        const npc_attack_rating &get_current_attack_evaluation() const {
+            return ai_cache.current_attack_evaluation;
+        }
+
         /**
          * Global position, expressed in map square coordinate system
          * (the most detailed coordinate system), used by the @ref map.