Fix monsters not using doors.

Previously, monsters would only open doors if they were straight on
the way to their target.

E.g.:

@#g
.+.

g won't open the door if its target is @. This can be reproduced for
example as follows (eg Sprint 1 start):

.1#3.
..+.2
..###

Stand at one, open door, place monster at 2, close door.
The monster will move to 3 and wait there until you open
the door.

I'm not sure why monsters didn't fall back to pathfinding if they
couldn't get to you directly.

These changes also unify some monster traversability checks between
mon-pathfind and mon-act.

1 files changed, 2 insertions, 2 deletions

diff --git a/crawl-ref/source/mon-pathfind.h b/crawl-ref/source/mon-pathfind.h
index 9507680f31..4be31dbed1 100644
--- a/crawl-ref/source/mon-pathfind.h
+++ b/crawl-ref/source/mon-pathfind.h
@@ -26,9 +26,9 @@ public:
 protected:
     // protected methods
     bool calc_path_to_neighbours(void);
-    bool traversable(coord_def p);
+    bool traversable(const coord_def& p);
     int  travel_cost(coord_def npos);
-    bool mons_traversable(coord_def p);
+    bool mons_traversable(const coord_def& p);
     int  mons_travel_cost(coord_def npos);
     int  estimated_cost(coord_def npos);
     void add_new_pos(coord_def pos, int total);