Fix taxes with non-taxing buildings.

src/common/gamecode/economy.c

@@ -3210,6 +3210,33 @@ auto_work(region * r)
   }
 }
 
+static building *
+taxbuilding(const region * r)
+{
+  building *b, *best = NULL;
+  double maxmoney = 0;
+  /* durch die verw. von '>' statt '>=' werden die aelteren burgen
+  * bevorzugt. */
+
+  if (r->land && r->land->ownership) {
+    for (b = rbuildings(r); b; b = b->next) {
+      if (b->type->taxes && r->land->ownership) {
+        const attrib * a = a_find(b->attribs, &at_icastle);
+        if (!a) {
+          int maxsize = buildingeffsize(b, false);
+          double money = b->type->taxes(b, maxsize);
+          if (money>0 && (best==NULL || money > maxmoney)) {
+            maxmoney = money;
+            best = b;
+          }
+        }
+      }
+    }
+  }
+  return best;
+}
+
+
 static void
 peasant_taxes(region * r)
 {
@@ -3226,7 +3253,7 @@ peasant_taxes(region * r)
   money = rmoney(r);
   if (money<=0) return;
 
-  b = largestbuilding(r, &is_owner_building, false);
+  b = taxbuilding(r);
   if (b==NULL) return;
 
   u = buildingowner(r, b);