Fix vm code base so that it can be built for --arch=simarm (no snapshot yet).

runtime/vm/assembler_arm.cc

Index: runtime/vm/assembler_arm.cc
===================================================================
--- runtime/vm/assembler_arm.cc	(revision 0)
+++ runtime/vm/assembler_arm.cc	(revision 0)
@@ -0,0 +1,19 @@
+// Copyright (c) 2013, 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.
+
+#include "vm/globals.h"
+#if defined(TARGET_ARCH_ARM)
+
+#include "vm/assembler.h"
+
+namespace dart {
+
+DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
+DEFINE_FLAG(bool, code_comments, false,
+            "Include comments into code and disassembly");
+
+}  // namespace dart
+
+#endif  // defined TARGET_ARCH_ARM
+