在Centos 7上为composer安装PHP intl扩展时发生冲突

I am trying to do a Magento 2 DRC installation on a remote linux server, running Centos 7, Apache 2.4.6, MariaDB and PHP v5.6.9. When I try to install Composer I get the following message:I am trying to do a Magento 2 DRC installation