I made a Release config and put these as macros:
//GMLIVE #macro live_enabled 1 #macro Release:live_enabled 0
And in obj_gmlive's Create Event I tweaked it like so:
if (live_enabled) { live_init(NULL, "http://localhost:5100", ""); }
So when I choose the Release config I don't get the "HttpError:HttpSendRequest: A connection with the server could not be established" message so it seems like it's turned GMLive off