Declare all configuration variables in optlist.h. Include that

instead of declaring them all over the place.  This uncovered type
errors:
(s_p_etu, adj_update): Defined long, sometimes declared int.  Kills
big endian machines where sizeof(long) != sizeof(int).  Change to
int.

(set_option, delete_option, optstrset, intset, floatset, doubleset,
longset, optionset, optiondel, worldxset): Change linkage to static.

src/lib/commands/mark.c

@@ -62,7 +62,6 @@ pr_mark(struct comstr *comm)
 {
     time_t now;
     double tleft;
-    extern int MARK_DELAY;
 
     (void)time(&now);
     tleft = MARK_DELAY / 3600.0 - (now - comm->com_markettime) / 3600.0;