fix ie8 object.create

lib/ace/lib/es5-shim.js

@@ -543,10 +543,33 @@ if (!Object.getOwnPropertyNames) {
 // ES5 15.2.3.5
 // http://es5.github.com/#x15.2.3.5
 if (!Object.create) {
+    var createEmpty;
+    if (Object.prototype.__proto__ === null) {
+        createEmpty = function () {
+            return { "__proto__": null };
+        };
+    } else {
+        // In old IE __proto__ can't be used to manually set `null`
+        createEmpty = function () {
+            var empty = {};
+            for (var i in empty)
+                empty[i] = null;
+            empty.constructor =
+            empty.hasOwnProperty =
+            empty.propertyIsEnumerable =
+            empty.isPrototypeOf =
+            empty.toLocaleString =
+            empty.toString =
+            empty.valueOf =
+            empty.__proto__ = null;
+            return empty;
+        }
+    }
+
     Object.create = function create(prototype, properties) {
         var object;
         if (prototype === null) {
-            object = { "__proto__": null };
+            object = createEmpty();
         } else {
             if (typeof prototype != "object")
                 throw new TypeError("typeof prototype["+(typeof prototype)+"] != 'object'");