more code that fails when there are no luxuries

src/common/gamecode/economy.c

@@ -2067,8 +2067,9 @@ expandselling(region * r, request * sellorders, int limit)
 
 			if (++counter[i] > max_products) {
 				int d = r_demand(r, ltype);
-				if (d > 1)
+        if (d > 1) {
           r_setdemand(r, ltype, d-1);
+        }
 				counter[i] = 0;
 			}
 		}

src/common/kernel/region.c

@@ -670,6 +670,9 @@ void
 r_setdemand(region * r, const luxury_type * ltype, int value)
 {
 	struct demand * d, ** dp = &r->land->demands;
+
+  if (ltype==NULL) return;
+
 	while (*dp && (*dp)->type != ltype) dp = &(*dp)->next;
 	d = *dp;
 	if (!d) {