diff --git a/src/c/mem_bdwgc.d b/src/c/mem_bdwgc.d
index 6c4cb4421..3f75da456 100644
--- a/src/c/mem_bdwgc.d
+++ b/src/c/mem_bdwgc.d
@@ -283,10 +283,12 @@ alloc_object(cl_type t)
 
   /* GC_MALLOC already resets objects */
   switch (t) {
-  case t_fixnum:
-    return ecl_make_fixnum(0); /* Immediate fixnum */
+  case t_list:                  /* Small cons (no d.t) */
+    return ecl_cons(ECL_NIL, ECL_NIL);
   case t_character:
-    return ECL_CODE_CHAR(' '); /* Immediate character */
+    return ECL_CODE_CHAR(' ');  /* Immediate character */
+  case t_fixnum:
+    return ecl_make_fixnum(0);  /* Immediate fixnum */
 #ifdef ECL_SSE2
   case t_sse_pack:
 #endif
@@ -368,26 +370,6 @@ ecl_alloc_compact_object(cl_type t, cl_index extra_space)
   return x;
 }
 
-cl_object
-ecl_cons(cl_object a, cl_object d)
-{
-  const cl_env_ptr the_env = ecl_process_env();
-  struct ecl_cons *obj;
-  ecl_disable_interrupts_env(the_env);
-  obj = GC_MALLOC(sizeof(struct ecl_cons));
-  ecl_enable_interrupts_env(the_env);
-#ifdef ECL_SMALL_CONS
-  obj->car = a;
-  obj->cdr = d;
-  return ECL_PTR_CONS(obj);
-#else
-  obj->t = t_list;
-  obj->car = a;
-  obj->cdr = d;
-  return (cl_object)obj;
-#endif
-}
-
 cl_object
 ecl_alloc_instance(cl_index slots)
 {
diff --git a/src/c/memory.d b/src/c/memory.d
index da393f447..44dfff39b 100644
--- a/src/c/memory.d
+++ b/src/c/memory.d
@@ -117,6 +117,38 @@ ecl_free_memory(void *ptr)
   return ecl_core.allocator->free_memory(ptr);
 }
 
+/* -- Helpers --------------------------------------------------------------- */
+
+cl_object
+ecl_cons(cl_object a, cl_object d)
+{
+  struct ecl_cons *obj = ecl_alloc_memory(sizeof(struct ecl_cons));
+#ifdef ECL_SMALL_CONS
+  obj->car = a;
+  obj->cdr = d;
+  return ECL_PTR_CONS(obj);
+#else
+  obj->t = t_list;
+  obj->car = a;
+  obj->cdr = d;
+  return (cl_object)obj;
+#endif
+}
+
+cl_object
+ecl_append_unsafe(cl_object x, cl_object y)
+{
+  cl_object head = ECL_NIL, cons;
+  cl_object *tail = &head;
+  loop_for_on_unsafe(x) {
+    cons = ecl_list1(ECL_CONS_CAR(x));
+    *tail = cons;
+    tail = &ECL_CONS_CDR(cons);
+  } end_loop_for_on_unsafe(x);
+  *tail = y;
+  return head;
+}
+
 /* -- Rudimentary manual memory allocator ----------------------------------- */
 
 static cl_object