when reading alliances, duplicate ids are impossible.

makealliance does too much work, new_alliance is simpler.

src/kernel/alliance.c

@@ -58,7 +58,7 @@ void free_alliances(void)
 
 alliance *makealliance(int id, const char *name)
 {
-    alliance *al;;
+    alliance *al;
 
     for (;;) {
         if (id > 0) {
@@ -73,6 +73,13 @@ alliance *makealliance(int id, const char *name)
         }
         id = id ? id : (1 + (rng_int() % MAX_UNIT_NR));
     }
+    return new_alliance(id, name);
+}
+
+alliance *new_alliance(int id, const char *name) {
+    alliance *al;
+    assert(id>0);
+
     al = calloc(1, sizeof(alliance));
     al->id = id;
     if (name) {

src/kernel/alliance.h

@@ -54,13 +54,14 @@ extern "C" {
     } alliance;
 
     extern alliance *alliances;
-    extern alliance *findalliance(int id);
-    extern alliance *makealliance(int id, const char *name);
-    extern const char *alliancename(const struct alliance *al);
-    extern void setalliance(struct faction *f, alliance * al);
+    alliance *findalliance(int id);
+    alliance *new_alliance(int id, const char *name);
+    alliance *makealliance(int id, const char *name);
+    const char *alliancename(const struct alliance *al);
+    void setalliance(struct faction *f, alliance * al);
     void free_alliances(void);
-    extern struct faction *alliance_get_leader(struct alliance *al);
-    extern void alliance_cmd(void);
+    struct faction *alliance_get_leader(struct alliance *al);
+    void alliance_cmd(void);
     bool is_allied(const struct faction *f1, const struct faction *f2);
 
     void alliance_setname(alliance * self, const char *name);

src/kernel/save.c

@@ -436,7 +436,7 @@ static void read_alliances(struct gamedata *data)
         char aname[128];
         alliance *al;
         READ_STR(store, aname, sizeof(aname));
-        al = makealliance(id, aname);
+        al = new_alliance(id, aname);
         if (data->version >= OWNER_2_VERSION) {
             READ_INT(store, &al->flags);
         }