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/show.c

@@ -51,7 +51,6 @@ show(void)
     struct natstr *natp;
     int tlev;
     s_char buf[1024];
-    extern float drnuke_const;
     int rlev;
 
     if (!(p = getstarg(player->argp[1],