diff --git a/runtime.c b/runtime.c
index 616a4144..71cf69a9 100644
--- a/runtime.c
+++ b/runtime.c
@@ -5684,7 +5684,10 @@ void GC(void *data, closure cont, object * args, int num_args)
 
 void Cyc_make_shared_object(void *data, object k, object obj)
 {
+  gc_thread_data *thd = (gc_thread_data *)data;
+  gc_heap_root *heap = thd->heap;
   object buf[1];
+  int tmp, *heap_grown = &tmp;
   if (!is_object_type(obj) || // Immediates do not have to be moved
       gc_is_stack_obj(data, obj)) { // Not thread-local, assume already on heap
     return_closcall1(data, k, obj);