安装此php版本前必须先安装另两篇Apche和myql安装环境，因为路径都是按照这两篇为基础的

安装PHP

安装yum环境（aliyun的yum环境）

[root@minion-1 ~]#yum -y install bzip2-devel libmcrypt-devel libxml2-devel libjpeg-devel libpng-devel freetype-devel
下载php5.6.40，去官网php或者直接在迅雷里下载(http://hk2.php.net/distributions/php-5.6.40.tar.gz)
解压php压缩包

[root@minion-1 ~]#tar xf php-5.6.40.tar.gz
进入目录,设置编译环境

[root@minion-1 php-5.6.40]#cd php-5.6.40/ && ./configure –prefix=/usr/local/php –with-apxs2=/usr/local/apache2.4/bin/apxs –with-mysql=/usr/local/mysql –with-pdo-mysql=/usr/local/mysql –with-mysqli=/usr/local/mysql/bin/mysql_config –with-libxml-dir –with-gd –with-jpeg-dir –with-png-dir –with-freetype-dir –with-icony-dir –with-zlib-dir –with-bz2 –with-openssl –with-mcrypt –enable-soap –enable-gd-nativ-ttf –enable-mbstring –enable-sockets –enable-exif
make编译

[root@minion-1 php-5.6.40]#make && make install

完美安装centos7编译安装php5.6.40(亲测成功！）