https://www.php.net/ 官网
https://museum.php.net/php7/ 所有老版本列表
用phpize方式安
cd php-7.1.22/ext/pcntl
/usr/local/php/bin/phpize
./configure --enable-pcntl --with-php-config=/usr/local/php/bin/php-config
make && make install
echo "extension=pcntl.so" >> /usr/local/php/etc/php.ini