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

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 27984)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -3789,6 +3789,17 @@
 }
 
 
+// --- Configurations ---
+DART_EXPORT Dart_Handle Dart_SetConfigCallback(
+    Dart_ConfigCallback callback) {
+  Isolate* isolate = Isolate::Current();
+  CHECK_ISOLATE(isolate);
+  isolate->set_config_callback(callback);
+  return Api::Success();
+}
+
+
+// --- Scripts and Libraries ---
 DART_EXPORT void Dart_SetBooleanReturnValue(Dart_NativeArguments args,
                                             bool retval) {
   TRACE_API_CALL(CURRENT_FUNC);