之前已经编译好了nginx，但是此时需要添加一个未被编译的模块，此处以--with-http_realip_module为例。
1、查看当前nginx编译安装时安装了哪些模块
nginx -V
nginx version: nginx/1.12.2
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-16) (GCC)
built with OpenSSL 1.0.2k-fips
TLS SNI support enabled
configure arguments: --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_gzip_static_module --with-http_sub_module
2、加入--with-http_sub_module模块，重新编译（ 注意：最后不需要执行make install）
cd /usr/local/src/
wget http://nginx.org/download/nginx-1.12.2.tar.gz
tar zxf nginx-1.12.2.tar.gz
cd /usr/local/src/nginx-1.12.2
./configure --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_gzip_static_module --with-http_sub_module --with-http_realip_module
make
3、备份源文件并替换nginx的二进制文件
mv /usr/local/nginx/sbin/nginx /usr/local/nginx/sbin/nginx.bak
cp objs/nginx /usr/local/nginx/sbin/nginx
4、验证
nginx -V
nginx version: nginx/1.12.2
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-16) (GCC)
built with OpenSSL 1.0.2k-fips
TLS SNI support enabled
configure arguments: --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_gzip_static_module --with-http_sub_module --with-http_realip_module
