checking for MySQL support… yes, shared checking for specified location of the MySQL UNIX socket… no checking for the location of libz… no checking for MySQL UNIX socket location… /var/lib/mysql/mysql.sock configure: error: Cannot find libmysqlclient under /usr. Note that the MySQL client library is not bundled anymore!

经查，问题是64位系统中 libmysqlclient 默认安装到了 /usr/lib64/mysql/ 目录下
而/usr/lib 目录下没有相应文件，但是php编译时，要去 /usr/lib目录下查找

解决方法：
cp /usr/lib64/mysql/* /usr/lib/