With EASY_BRIDGES on, bridge spans need to be next to land or a bridge
tower to remain standing.
Land can't go away, but a bridge tower can fall. Bridge spans next to
it may lose support then. Bug: they don't fall when they lose support
that way. Fix that.
Broken in commit 40eb78e, v4.3.12.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Stuff sitting on bridges isn't covered, yet. tests/fire has some. To
be moved here eventually.
The test exposes bugs. They're marked "BUG:" in the test input.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
