Fix sort_script causing program crash

src/interfaces.cpp

@@ -1268,7 +1268,7 @@ std::string subconverter(RESPONSE_CALLBACK_ARGS)
     ext.skip_cert_verify.define(scv_flag);
 
     ext.sort_flag = sort_flag.get(do_sort);
-    use_sort_script.define(sort_script.size());
+    use_sort_script.define(sort_script.size() != 0);
     if(ext.sort_flag && use_sort_script)
         ext.sort_script = sort_script;
     ext.filter_deprecated = fdn.get(filter_deprecated);

src/subexport.cpp

@@ -1023,6 +1023,7 @@ void preprocessNodes(std::vector<nodeInfo> &nodes, extra_settings &ext)
                         duktape_push_nodeinfo(ctx, a);
                         duktape_push_nodeinfo(ctx, b);
                         /// call function
+                        duk_pcall(ctx, 2);
                         return duktape_get_res_int(ctx);
                     };
                     std::sort(nodes.begin(), nodes.end(), comparer);