我正在使用 CentOS 7 64 位运行专用服务器，这是尝试安装 IMAP 时的输出：
yum install php-imap
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: ftp.ciril.fr
* extras: ftp.ciril.fr
* updates: ftp.ciril.fr
No package php-imap available.
Error: Nothing to do
禁用排除项时也一样：
sudo yum install --disableexcludes=all php-imap
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: ftp.ciril.fr
* extras: ftp.ciril.fr
* updates: ftp.ciril.fr
No package php-imap available.
Error: Nothing to do