fix safari syntax error - decalring twice

fix mishoo#1753.
to mangle names properly - to avoid safari error -, scope of for loop should enclose parent scope variables

Signed-off-by: Gyusun Yeom <omniavinco@gmail.com>

lib/scope.js

@@ -122,6 +122,12 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
                 scope.uses_eval = save_scope.uses_eval;
                 scope.directives = save_scope.directives;
             }
+            // issue 1753 - name mangling in for loop scope should consider parent scope
+            if (node instanceof AST_For) {
+                save_scope.variables.each(function(def) {
+                    push_uniq(scope.enclosed, def);
+                });
+            }
             descend();
             scope = save_scope;
             return true;