autopickup_exceptions enhancement

An enhancement to the original to allow
two types of exceptions:
      always pickup
      never pickup

To specify "never pickup", begin the pattern string with '>'
which is NetHack's down direction symbol (for "leave it down")

To specify "always pickup", begin the pattern string with '<'
which is NetHack's up direction symbol.

For example, to pick up all arrows, regardless of the pickup_
types setting:
autopickup_exception = "<*arrows"

include/extern.h

@@ -1513,6 +1513,7 @@ E int FDECL(loot_mon, (struct monst *,int *,boolean *));
 E int NDECL(dotip);
 E const char *FDECL(safe_qbuf, (const char *,unsigned,
 				const char *,const char *,const char *));
+E boolean FDECL(is_autopickup_exception, (struct obj *, BOOLEAN_P));
 
 /* ### pline.c ### */