- Implement a first cut for const String.env in the VM to allow

sdk/lib/core/int.dart

Index: sdk/lib/core/int.dart
===================================================================
--- sdk/lib/core/int.dart	(revision 28841)
+++ sdk/lib/core/int.dart	(working copy)
@@ -252,4 +252,12 @@
   external static int parse(String source,
                             { int radix,
                               int onError(String source) });
+
+  /**
+   * Returns the integer value of the given environment variable [name].
+   * The [defaultValue] is returned if [name] is not present in the environment
+   * or if its value is not an integer.
+   */
+  external const factory int.fromEnvironment(String name,
+                                             {int defaultValue: 0});
 }