Bump to v4.0.0.

internal/checkGlobal.js

@@ -0,0 +1,15 @@
+define([], function() {
+
+  /**
+   * Checks if `value` is a global object.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {null|Object} Returns `value` if it's a global object, else `null`.
+   */
+  function checkGlobal(value) {
+    return (value && value.Object === Object) ? value : null;
+  }
+
+  return checkGlobal;
+});