android系统编译打开系统蓝牙

在项目配置文件ProjectConfig.mk中开启蓝牙以后，但是设置菜单中并没有出现蓝牙选项，最后发现是因为ProjectConfig.mk同级目录下没有蓝牙配置文件android.hardware.bluetooth.xml，该文件内容如下

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2009 The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->

<!-- This is the standard feature indicating that the device includes Bluetooth. -->
<permissions>
<feature name="android.hardware.bluetooth" />
</permissions>