No package libmcrypt available.

Centos安装PHP时，安装php依赖包时yum install libmcrypt libmcrypt-devel，报错如下：

No package libmcrypt available.
No package libmcrypt-devel available.
Error: Nothing to do

然后编译的时候，又报错：

checking for mcrypt support... yes
configure: error: mcrypt.h not found. Please reinstall libmcrypt.

解决方法：yum  install epel-release  //扩展包更新包