Fix build.

Former-commit-id: b894b652c8c566411bb47935b67d649a2e6461e7

dist/lodash.underscore.js

@@ -18,8 +18,8 @@
   /** Used internally to indicate various things */
   var indicatorObject = {};
 
-  /** Used to avoid reference errors in `createIterator` */
-  var iteratorObject = {};
+  /** Used to avoid reference errors and circular dependency errors */
+  var dependencyObject = {};
 
   /** Used to prefix keys to avoid issues with `__proto__` and properties on `Object.prototype` */
   var keyPrefix = +new Date + '';
@@ -619,7 +619,7 @@
    * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
    * // => ['one', 'two', 'three'] (order is not guaranteed)
    */
-  var keys = iteratorObject.keys = !nativeKeys ? shimKeys : function(object) {
+  var keys = dependencyObject.keys = !nativeKeys ? shimKeys : function(object) {
     if (!isObject(object)) {
       return [];
     }
@@ -1051,7 +1051,7 @@
    * });
    * // => true
    */
-  function isEqual(a, b, stackA, stackB) {
+  var isEqual = dependencyObject.isEqual = function(a, b, stackA, stackB) {
     if (a === b) {
       return a !== 0 || (1 / a == 1 / b);
     }
@@ -1147,7 +1147,7 @@
       });
     }
     return result;
-  }
+  };
 
   /**
    * Checks if `value` is, or can be coerced to, a finite number.