我使用 Homebrew 安装了 PHP brew install php。
php -v给我：
PHP 8.0.9 (cli) (built: Jul 29 2021 17:21:21) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.9, Copyright (c) Zend Technologies
with Zend OPcache v8.0.9, Copyright (c), by Zend Technologies
这样 PHP 就安装成功了，并且也作为一个服务运行在brew services start php.
要安装 xdebug，我使用的命令pecl install xdebug似乎工作正常，但最后我收到消息：
Build process completed successfully
Installing '/usr/local/Cellar/php/8.0.9/pecl/20200930/xdebug.so'
Warning: mkdir(): File exists in System.php on line 294
PHP Warning: mkdir(): File exists in /usr/local/Cellar/php/8.0.9/share/php/pear/System.php on …