Bump to v4.0.0.

internal/getSymbols.js

@@ -0,0 +1,18 @@
+define([], function() {
+
+  /** Built-in value references. */
+  var getOwnPropertySymbols = Object.getOwnPropertySymbols;
+
+  /**
+   * Creates an array of the own symbol properties of `object`.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @returns {Array} Returns the array of symbols.
+   */
+  var getSymbols = getOwnPropertySymbols || function() {
+    return [];
+  };
+
+  return getSymbols;
+});