refactor new_border's relationship to nextborder.

loading a connection was unnecessarily changing nextborder.

src/kernel/connection.c

@@ -106,7 +106,7 @@ connection *get_borders(const region * r1, const region * r2)
     return *bp;
 }
 
-connection *new_border(border_type * type, region * from, region * to)
+connection *new_border(border_type * type, region * from, region * to, int id)
 {
     connection *b, **bp;
 
@@ -120,10 +120,11 @@ connection *new_border(border_type * type, region * from, region * to)
     b->type = type;
     b->from = from;
     b->to = to;
-    b->id = ++nextborder;
+    b->id = (id > 0) ? id : ++nextborder;
 
-    if (type->init)
+    if (type->init) {
         type->init(b);
+    }
     return b;
 }
 
@@ -612,9 +613,7 @@ int read_borders(gamedata *data)
                 }
             }
             if (b == NULL) {
-                b = new_border(type, from, to);
-                nextborder--;               /* new_border erhoeht den Wert */
-                b->id = bid;
+                b = new_border(type, from, to, bid);
                 assert(bid <= nextborder);
             }
             type->read(b, data);

src/kernel/connection.h

@@ -86,8 +86,7 @@ extern "C" {
     connection *get_borders(const struct region *r1,
         const struct region *r2);
     /* returns the list of borders between r1 and r2 or r2 and r1 */
-    connection *new_border(border_type * type, struct region *from,
-    struct region *to);
+    connection *new_border(border_type *type, struct region *from, struct region *to, int id);
     /* creates a connection of the specified type */
     void erase_border(connection * b);
     /* remove the connection from memory */

src/kernel/region.c

@@ -539,7 +539,7 @@ void rsetroad(region * r, direction_t d, int val)
     }
     if (!b) {
         if (!val) return;
-        b = new_border(&bt_road, r, r2);
+        b = new_border(&bt_road, r, r2, 0);
     }
     if (r == b->from) {
         b->data.sa[0] = (short)val;

src/spells.c

@@ -2657,7 +2657,7 @@ static int sp_firewall(castorder * co)
         b = b->next;
     }
     if (b == NULL) {
-        b = new_border(&bt_firewall, r, r2);
+        b = new_border(&bt_firewall, r, r2, 0);
         fd = (wall_data *)b->data.v;
         fd->force = (int)(force / 2 + 0.5);
         fd->mage = caster;
@@ -3094,7 +3094,7 @@ static int sp_chaossuction(castorder * co)
     /* TODO: implement with a building */
     create_special_direction(r, rt, 2, "vortex_desc", "vortex", false);
     create_special_direction(rt, r, 2, "vortex_desc", "vortex", false);
-    new_border(&bt_chaosgate, r, rt);
+    new_border(&bt_chaosgate, r, rt, 0);
 
     ADDMSG(&r->msgs, msg_message("chaosgate_effect_1", "mage", caster));
     ADDMSG(&rt->msgs, msg_message("chaosgate_effect_2", ""));