Add the beginnings of a Dart wrapper for libarchive.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index d9c7d9820690c3503d3d5bb4034990c8398f1ada..6875140dba0472744a619b5600da9e41102141b2 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -5606,7 +5606,7 @@ void NewNativePort_send321(Dart_Port dest_port_id,
 UNIT_TEST_CASE(NewNativePort) {
   // Create a port with a bogus handler.
   Dart_Port error_port = Dart_NewNativePort("Foo", NULL, true);
-  EXPECT_EQ(kIllegalPort, error_port);
+  EXPECT_EQ(ILLEGAL_PORT, error_port);
 
   // Create the port w/o a current isolate, just to make sure that works.
   Dart_Port port_id1 =