Index: uspace/lib/cpp/include/impl/memory.hpp
===================================================================
--- uspace/lib/cpp/include/impl/memory.hpp	(revision 537b300f24e8c19c411f63ebc05e76d50df16563)
+++ uspace/lib/cpp/include/impl/memory.hpp	(revision e13c378e9d5264d41d4fb768c87e72f027e44c2b)
@@ -1,4 +1,4 @@
 /*
- * Copyright (c) 2017 Jaroslav Jindrak
+ * Copyright (c) 2018 Jaroslav Jindrak
  * All rights reserved.
  *
@@ -31,4 +31,5 @@
 
 #include <internal/aux.hpp>
+#include <internal/memory/allocator_arg.hpp>
 #include <internal/memory/addressof.hpp>
 #include <iterator>
@@ -53,13 +54,4 @@
         using rebind = typename Ptr::template rebind<U>;
     };
-
-    /**
-     * 20.7.6, allocator argument tag:
-     */
-
-    struct allocator_arg_t
-    { /* DUMMY BODY */ };
-
-    constexpr allocator_arg_t allocator_arg{};
 
     /**
Index: uspace/lib/cpp/include/internal/memory/allocator_arg.hpp
===================================================================
--- uspace/lib/cpp/include/internal/memory/allocator_arg.hpp	(revision e13c378e9d5264d41d4fb768c87e72f027e44c2b)
+++ uspace/lib/cpp/include/internal/memory/allocator_arg.hpp	(revision e13c378e9d5264d41d4fb768c87e72f027e44c2b)
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2018 Jaroslav Jindrak
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LIBCPP_INTERNAL_MEMORY_ALLOCATOR_ARG
+#define LIBCPP_INTERNAL_MEMORY_ALLOCATOR_ARG
+
+namespace std
+{
+    /**
+     * 20.7.6, allocator argument tag:
+     */
+
+    struct allocator_arg_t
+    { /* DUMMY BODY */ };
+
+    constexpr allocator_arg_t allocator_arg{};
+}
+
+#endif