Comment 5 for bug 861840

The linked branch lp:~nha/widelands/buildcaps-ext provides a first stab at solving this issue. Basically, this re-imagined way to compute buildcaps requires each of the four fields occupied by big buildings to be (a) completely on regular buildable terrain and (b) not adjacent to bigger immovables on the map.

The branch does not handle ports yet. There are two possible ways to go forward for ports:
(1) Have port spaces be a subset of fields where big buildings are built, just that ports may then be slightly further away from the coastline than they were previously, or
(2) Introduce special treatment for port spaces that allows the l/tl/tr fields of ports to be on the coast line.
Right now, I'm leaning towards (1).