--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/libgnat/a-cusyqu.adb	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,174 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT LIBRARY COMPONENTS                          --
+--                                                                          --
+--               ADA.CONTAINERS.UNBOUNDED_SYNCHRONIZED_QUEUES               --
+--                                                                          --
+--                                 B o d y                                  --
+--                                                                          --
+--            Copyright (C) 2011-2017, Free Software Foundation, Inc.       --
+--                                                                          --
+-- GNAT is free software;  you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- This unit was originally developed by Matthew J Heaney.                  --
+------------------------------------------------------------------------------
+
+with Ada.Unchecked_Deallocation;
+
+package body Ada.Containers.Unbounded_Synchronized_Queues is
+
+   package body Implementation is
+
+      -----------------------
+      -- Local Subprograms --
+      -----------------------
+
+      procedure Free is
+         new Ada.Unchecked_Deallocation (Node_Type, Node_Access);
+
+      -------------
+      -- Dequeue --
+      -------------
+
+      procedure Dequeue
+        (List    : in out List_Type;
+         Element : out Queue_Interfaces.Element_Type)
+      is
+         X : Node_Access;
+
+      begin
+         Element := List.First.Element;
+
+         X := List.First;
+         List.First := List.First.Next;
+
+         if List.First = null then
+            List.Last := null;
+         end if;
+
+         List.Length := List.Length - 1;
+
+         Free (X);
+      end Dequeue;
+
+      -------------
+      -- Enqueue --
+      -------------
+
+      procedure Enqueue
+        (List     : in out List_Type;
+         New_Item : Queue_Interfaces.Element_Type)
+      is
+         Node : Node_Access;
+
+      begin
+         Node := new Node_Type'(New_Item, null);
+
+         if List.First = null then
+            List.First := Node;
+            List.Last := List.First;
+
+         else
+            List.Last.Next := Node;
+            List.Last := Node;
+         end if;
+
+         List.Length := List.Length + 1;
+
+         if List.Length > List.Max_Length then
+            List.Max_Length := List.Length;
+         end if;
+      end Enqueue;
+
+      --------------
+      -- Finalize --
+      --------------
+
+      procedure Finalize (List : in out List_Type) is
+         X : Node_Access;
+
+      begin
+         while List.First /= null loop
+            X := List.First;
+            List.First := List.First.Next;
+            Free (X);
+         end loop;
+      end Finalize;
+
+      ------------
+      -- Length --
+      ------------
+
+      function Length (List : List_Type) return Count_Type is
+      begin
+         return List.Length;
+      end Length;
+
+      ----------------
+      -- Max_Length --
+      ----------------
+
+      function Max_Length (List : List_Type) return Count_Type is
+      begin
+         return List.Max_Length;
+      end Max_Length;
+
+   end Implementation;
+
+   protected body Queue is
+
+      -----------------
+      -- Current_Use --
+      -----------------
+
+      function Current_Use return Count_Type is
+      begin
+         return List.Length;
+      end Current_Use;
+
+      -------------
+      -- Dequeue --
+      -------------
+
+      entry Dequeue (Element : out Queue_Interfaces.Element_Type)
+        when List.Length > 0
+      is
+      begin
+         List.Dequeue (Element);
+      end Dequeue;
+
+      -------------
+      -- Enqueue --
+      -------------
+
+      entry Enqueue (New_Item : Queue_Interfaces.Element_Type) when True is
+      begin
+         List.Enqueue (New_Item);
+      end Enqueue;
+
+      --------------
+      -- Peak_Use --
+      --------------
+
+      function Peak_Use return Count_Type is
+      begin
+         return List.Max_Length;
+      end Peak_Use;
+
+   end Queue;
+
+end Ada.Containers.Unbounded_Synchronized_Queues;