lld-link: error: subsystem must be defined

[WhatMe Worry]

This is a beginner's question but how to I get past this?

C:\Users\Kyle\AppData\Local\dub\packages\arsd-official-7.2.0\arsd-official>lld-link terminal.obj

lld-link: error: subsystem must be defined

help mentions this option, but
  /subsystem:<value>      Specify subsystem

Is there a good tutorial for ldc2 because I haven't been able to 
find anything.