ExecStartPre has nginx -t to test the Nginx config before starting
the service initially but ExecReload will just issue an Nginx reload
without testing the config first. If the config ends up being bad
this takes Nginx down. Perform a config test before reloading and if
that fails leave Nginx running on the previous config in RAM.

Build NGINX from source with nginx.ng state with support for passing
compile time flags necessary for installing modules such as more headers
by the openresty project.