docker php容器中 Call to undefined function pcntl_fork() 解決方法
問題：docker容器中使用pcntl_fork函數(shù)，提示報(bào)錯(cuò)：
root@b7204f45ed02:/var/www/: php -r "echo pcntl_fork();";
PHP Fatal error: Uncaught Error: Call to undefined function pcntl_fork() in Command line code:1
Stack trace:
#0 {main}
thrown in Command line code on line 1
