fix non-places build

src/racket/gc2/mem_account.c

@@ -65,6 +65,7 @@ inline static void mark_threads(NewGC *gc, int owner)
         }
       } else {
         /* place */
+#ifdef MZ_USE_PLACES
         /* add in the memory used by the place's GC */
         intptr_t sz;
         Scheme_Place_Object *place_obj = ((Scheme_Place *)work->thread)->place_obj;
@@ -74,6 +75,7 @@ inline static void mark_threads(NewGC *gc, int owner)
           mzrt_mutex_unlock(place_obj->lock);
           account_memory(gc, owner, gcBYTES_TO_WORDS(sz));
         }
+#endif
       }
     }
   }

src/racket/src/schpriv.h

@@ -3724,7 +3724,9 @@ void scheme_socket_to_output_port(intptr_t s, Scheme_Object *name, int takeover,
 
 #define SCHEME_PLACE_OBJECTP(o) (SCHEME_TYPE(o) == scheme_place_object_type)
 
+#ifdef MZ_USE_PLACES
 Scheme_Env *scheme_place_instance_init(void *stack_base, struct NewGC *, intptr_t memory_limit);
+#endif
 Scheme_Object *scheme_make_place_object();
 void scheme_place_instance_destroy(int force);
 void scheme_kill_green_thread_timer();