compat/heap: add GCC's missing copyright notice

compat/heap.hpp

@@ -1,6 +1,54 @@
 #pragma once
 
 #if defined __GLIBCXX__ && defined _GLIBCXX_DEBUG
+// Heap implementation -*- C++ -*-
+
+// Copyright (C) 2001-2024 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// 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/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
 #include <utility>
 #include <iterator>
 // regular STL implementation stripped of debug code