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/util/fairland.c

@@ -185,7 +185,6 @@ main(int argc, char *argv[])
     int opt;
     extern int optind;
     extern char *optarg;
-    extern s_char *datadir;
     char *config_file = NULL;
     char tbuf[512];
     int i = 0;