bugfix terraforming in regionen ohne production

src/common/kernel/resources.c

@@ -65,6 +65,7 @@ terraform_resources(region * r)
   int i;
   const terrain_type * terrain = r->terrain;
 
+  if (terrain->production==NULL) return;
   for (i=0;terrain->production[i].type; ++i) {
     rawmaterial *rm;
     const terrain_production * production = terrain->production+i;