make migrants.formula a flag.

lookup in race.parameters was slow.
there is only one formula, anyhow.

src/kernel/faction.c

@@ -565,7 +565,7 @@ bool valid_race(const struct faction *f, const struct race *rc)
     else {
         const char *str = get_param(f->race->parameters, "other_race");
         if (str)
-            return (bool)(rc_find(str) == rc);
+            return rc_find(str) == rc;
         return false;
     }
 }

src/kernel/faction.test.c

@@ -202,7 +202,7 @@ static void test_max_migrants(CuTest *tc) {
     f = test_create_faction(rc);
     u = test_create_unit(f, test_create_region(0, 0, 0));
     CuAssertIntEquals(tc, 0, count_maxmigrants(f));
-    set_param(&rc->parameters, "migrants.formula", "1");
+    rc->flags |= RCF_MIGRANTS;
     CuAssertIntEquals(tc, 0, count_maxmigrants(f));
     scale_number(u, 250);
     CuAssertIntEquals(tc, 13, count_maxmigrants(f));

src/kernel/race.c

@@ -296,7 +296,7 @@ int rc_armor_bonus(const race *rc) {
 
 int rc_migrants_formula(const race *rc)
 {
-    return rc->parameters ? get_param_int(rc->parameters, "migrants.formula", MIGRANTS_NONE) : MIGRANTS_NONE;
+    return (rc->flags&RCF_MIGRANTS) ? MIGRANTS_LOG10 : MIGRANTS_NONE;
 }
 
 const char* rc_name(const race * rc, name_t n, char *name, size_t size) {

src/kernel/race.h

@@ -223,6 +223,7 @@ extern "C" {
 #define RCF_STONEGOLEM     (1<<27)      /* race gets stonegolem properties */
 #define RCF_IRONGOLEM      (1<<28)      /* race gets irongolem properties */
 #define RCF_ATTACK_MOVED   (1<<29)      /* may attack if it has moved */
+#define RCF_MIGRANTS       (1<<30)      /* may have migrant units (human bonus) */
 
     /* Economic flags */
 #define ECF_KEEP_ITEM       (1<<1)   /* gibt Gegenst<73>nde weg */

src/kernel/xmlreader.c

@@ -1737,6 +1737,11 @@ static int parse_races(xmlDocPtr doc)
                 if (strcmp((const char *)propName, "recruit_multi")==0) {
                     rc->recruit_multi = atof((const char *)propValue);
                 }
+                else if (strcmp((const char *)propName, "migrants.formula") == 0) {
+                    if (propValue[0] == '1') {
+                        rc->flags |= RCF_MIGRANTS;
+                    }
+                }
                 else {
                     set_param(&rc->parameters, (const char *)propName, (const char *)propValue);
                 }