GCC 对C语言的扩展
http://www.cnblogs.com/emituofo/archive/2012/07/20/2600995.html
http://blog.csdn.net/andyhuabing/article/details/42640705
https://my.oschina.net/senmole/blog/50710
http://blog.csdn.net/shangzh/article/details/39398577
http://nathanxu.blog.51cto.com/50836/56661/
http://nathanxu.blog.51cto.com/50836/6027/
http://nathanxu.blog.51cto.com/50836/56658/