get_adjacent_loc()

use get_adjacent_loc() rather than getdir() directly for some things where
you want to ensure valid adjacent coordinates are returned

<email deleted> wrote:
>>> [...]
>>> I've noticed that the loot adjacent spot code doesn't have any
>>> isok(x,y) test, so will risk crashing if used at the edge of
>>> the screen (whether deliberately, or accidentally due to being
>>> confused or stunned when picking the direction).

>> Would this not be a problem elsewhere, such as use_leash() too?

> Yes, that looks like the same risk. getdir() doesn't validate
> that the <u.ux+u.dx, u.uy,u.dy> is safe and neither does m_at(),
> so their callers need to.
>
> I did manage to provoke a crash with #loot on the plane of earth,
> although an accidental case would be a lot less likely to happen.

include/extern.h

@@ -172,6 +172,7 @@ E int FDECL(movecmd, (CHAR_P));
 E int FDECL(getdir, (const char *));
 E void NDECL(confdir);
 E int FDECL(isok, (int,int));
+E int FDECL(get_adjacent_loc, (const char *, const char *, XCHAR_P, XCHAR_P, coord *));
 E const char *FDECL(click_to_cmd, (int,int,int));
 E char NDECL(readchar);
 #ifdef WIZARD