The current targetting code in cmpAttack simply linearly extrapolates the movement of the last turn. This works in many cases, but is suboptimal in others. We can somewhat improve it, by estimating the position using the unitMotion. However we should also keep the old behaviour, see comments (otherwise players will do short straight moves). Somewhat idea from D3182.
This should work very will with D2837, D3021 and D3200.