Teamcity buildagent on mac, environment variable not visible to Teamcity

Having problems setting up a Mac as a buildagent for TeamCity. It works for basic builds, but I'm unable to meet build requirements for our main build.

Unmet requirements shown in Teamcity:
env.NGINX_EXE exists
(a few others too, but I'm gonna handle those when I get this one working)

I've installed NGINX, and it's running. The problem is that the environment variable I've created, doesn't register with TeamCity. What I did was add the following line to /etc/profile:
export NGINX_EXE=/usr/local/bin/nginx

– and restarted (several times).

Typing env in a terminal window lists the system variables as far as I know, and that list shows among other things:

NGINX_EXE=/usr/local/bin/nginx

I would have thought this was what was needed by TeamCity, but it still shows the requirement as unmet.

I don't really know Macs, I work with windows (and to a lesser degree – linux), so if you have any tips for me, bear that in mind.