Import LevelDB 1.5, it will be used for the transaction database.

src/leveldb/port/port.h

@@ -0,0 +1,19 @@
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef STORAGE_LEVELDB_PORT_PORT_H_
+#define STORAGE_LEVELDB_PORT_PORT_H_
+
+#include <string.h>
+
+// Include the appropriate platform specific file below.  If you are
+// porting to a new platform, see "port_example.h" for documentation
+// of what the new port_<platform>.h file must provide.
+#if defined(LEVELDB_PLATFORM_POSIX)
+#  include "port/port_posix.h"
+#elif defined(LEVELDB_PLATFORM_CHROMIUM)
+#  include "port/port_chromium.h"
+#endif
+
+#endif  // STORAGE_LEVELDB_PORT_PORT_H_