Introduce "platform configurations" to replace categories and libraries.dart.

sdk/lib/core/core_embedded.dart

Index: sdk/lib/core/core_embedded.dart
diff --git a/sdk/lib/core/core_embedded.dart b/sdk/lib/core/core_embedded.dart
new file mode 100644
index 0000000000000000000000000000000000000000..71926c963c7b7275fd7f37f2ec8a4694cf6cad0d
--- /dev/null
+++ b/sdk/lib/core/core_embedded.dart
@@ -0,0 +1,49 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Built-in types, collections, and other core functionality for embedded
+/// Fletch programs.
+library dart.core;
+
+import "dart:collection";
+import "dart:_internal" hide Symbol;
+import "dart:_internal" as internal show Symbol;
+import "dart:_convert" show UTF8, LATIN1, Encoding;
+import "dart:math" show Random;  // Used by List.shuffle.
+import "dart:_async" show Stream, Future;  // Used by Resource.
+
+part "annotations.dart";
+part "bool.dart";
+part "comparable.dart";
+part "date_time.dart";
+part "double.dart";
+part "duration.dart";
+part "errors.dart";
+part "exceptions.dart";
+part "expando.dart";
+part "function.dart";
+part "identical.dart";
+part "int.dart";
+part "invocation.dart";
+part "iterable.dart";
+part "iterator.dart";
+part "list.dart";
+part "map.dart";
+part "null.dart";
+part "num.dart";
+part "object.dart";
+part "pattern.dart";
+part "print.dart";
+part "regexp.dart";
+part "resource.dart";
+part "set.dart";
+part "sink.dart";
+part "stacktrace.dart";
+part "stopwatch.dart";
+part "string.dart";
+part "string_buffer.dart";
+part "string_sink.dart";
+part "symbol.dart";
+part "type.dart";
+part "uri.dart";