Enable dynamic modules support.
Bump PORTREVISION.

In case of usage following modules please update nginx configuration file
for load these modules:

load_module "modules/ngx_http_geoip_module.so";
load_module "modules/ngx_http_image_filter_module.so";
load_module "modules/ngx_http_xslt_filter_module.so";
load_module "modules/ngx_mail_module.so";
load_module "modules/ngx_stream_module.so";

See https://www.nginx.com/blog/dynamic-modules-nginx-1-9-11/ for details.