错误提示：
./configure: error: the HTTP cache module requires md5 functions
from OpenSSL library. You can either disable the module by using
--without-http-cache option, or install the OpenSSL library into the system,
or build the OpenSSL library statically from the source with nginx by using
--with-http\_ssl\_module --with-openssl= options.
解决方案
yum -y install openssl openssl-devel