fixes #157, renaming local library identifiers if needed.

lib/runtime/dart/_internal.js

Index: lib/runtime/dart/_internal.js
diff --git a/lib/runtime/dart/_internal.js b/lib/runtime/dart/_internal.js
index bbac3d6660d0499cb2056975a5d8a0c060d95a22..dfc6ab4881217545d4a3b9976a6fede13ce0315a 100644
--- a/lib/runtime/dart/_internal.js
+++ b/lib/runtime/dart/_internal.js
@@ -1,5 +1,5 @@
-var _internal;
-(function(exports) {
+var _internal, core, collection, math, _interceptors, _js_primitives;
+(function(exports, core, collection, math, _interceptors, _js_primitives) {
   'use strict';
   class EfficientLength extends core.Object {}
   let ListIterable$ = dart.generic(function(E) {
@@ -2040,4 +2040,4 @@ var _internal;
   exports.Sort = Sort;
   exports.Symbol = Symbol;
   exports.POWERS_OF_TEN = POWERS_OF_TEN;
-})(_internal || (_internal = {}));
+})(_internal || (_internal = {}), core, collection, math || (math = {}), _interceptors || (_interceptors = {}), _js_primitives || (_js_primitives = {}));