安装php xdebug扩展

xdebug的php作用有很多，我使用的原因是可以结合phpunit，通过单元测试查看代码覆盖率，作为自测参考。

安装步骤如下，其实就是源码目录中的READ文件内容（任何开源代码的README文件都很有必要读读），十分简单，希望对你有用，

1. Unpack the tarball: tar -xzf xdebug-2.2.x.tgz.  Note that you do
not need to unpack the tarball inside the PHP source code tree.
Xdebug is compiled separately, all by itself, as stated above.

2. cd xdebug-2.2.x

3. Run phpize: phpize
   (or /path/to/phpize if phpize is not in your path).

4. ./configure --enable-xdebug (or: ../configure --enable-xdebug
   --with-php-config=/path/to/php-config if php-config is not in your
   path)

5. Run: make

6. cp modules/xdebug.so /to/wherever/you/want/it

7. add the following line to php.ini:
   zend_extension="/wherever/you/put/it/xdebug.so"

8. Restart your webserver.

9. Write a PHP page that calls "phpinfo();" Load it in a browser and
   look for the info on the xdebug module.  If you see it, you have been
   successful!