Fleshing out the mechanics:
- Add a value "rations" to the units
- Init at around 5 when you recruit a new unit
- When your unit would suffer from starvation, but has rations, reduce rations by 1 instead
- When you are stationary in a region with food surplus, it slowly replenishes (say, 0.2 per day)
- You can loot for rations, the old "steal food" option
- When you're out of rations, starvation sets in
