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/edit.c

@@ -690,7 +690,6 @@ static int
 docountry(s_char op, int arg, s_char *p, float farg, natid nat,
 	  struct natstr *np)
 {
-    extern int m_m_p_d;
     coord newx, newy;
     switch (op) {
     case 'n':