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/subs/takeover.c

@@ -64,8 +64,6 @@ takeover(register struct sctstr *sp, natid newown)
     struct nstr_item ni;
     struct plnstr p;
     struct lndstr land;
-    extern int etu_per_update;
-    extern int sect_mob_neg_factor;
 
     /* Wipe all the distribution info */
     memset(vec, 0, sizeof(vec));