在linux下编译nodejs 的C++ addon ，在windows下都是OK的，结果到了ubuntu下反而报错了，错误大概如下：
gyp ERR! Completion callback never invoked
搞了很久，各种搜索都找不到方法，后边进github里面看了下readme,尝试把npm 和node-pyg的pyhon路径设置了一下就可以了。
Configuring Python Dependency配置依赖
If you have multiple Python versions installed, you can identify which Python version node-gyp uses by setting the --pythonvariable:
$ node-gyp --python /user/bin/python2.7
If node-gyp is called by way of npm, and you have multiple versions of Python installed, then you can set npm‘s ‘python’ config key to the appropriate value:
$ npm config set python /user/bin/python2.7