Bump to v4.0.0.

internal/cloneRegExp.js

@@ -0,0 +1,22 @@
+define([], function() {
+
+  /** Used to match `RegExp` flags from their coerced string values. */
+  var reFlags = /\w*$/;
+
+  /**
+   * Creates a clone of `regexp`.
+   *
+   * @private
+   * @param {Object} regexp The regexp to clone.
+   * @returns {Object} Returns the cloned regexp.
+   */
+  function cloneRegExp(regexp) {
+    var Ctor = regexp.constructor,
+        result = new Ctor(regexp.source, reFlags.exec(regexp));
+
+    result.lastIndex = regexp.lastIndex;
+    return result;
+  }
+
+  return cloneRegExp;
+});