redundant includes

Remove several duplicate includes I discovered while reconciling the
vms Makefile.  All of these are already being brought in via hack.h so don't
need to be explicitly included after it.

src/decl.c

@@ -40,7 +40,6 @@ NEARDATA int in_doagain = 0;
  */
 struct dgn_topology dungeon_topology = {DUMMY};
 
-#include "quest.h"
 struct q_score	quest_status = DUMMY;
 
 NEARDATA int warn_obj_cnt = 0;