aarch64: free tlsdesc data on dlclose [BZ #27403]

DL_UNMAP_IS_SPECIAL and DL_UNMAP were not defined. The definitions are
now copied from arm, since the same is needed on aarch64. The cleanup
of tlsdesc data is handled by the custom _dl_unmap.

Fixes bug 27403.

sysdeps/aarch64/dl-lookupcfg.h

@@ -0,0 +1,27 @@
+/* Configuration of lookup functions.
+   Copyright (C) 2006-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#define DL_UNMAP_IS_SPECIAL
+
+#include_next <dl-lookupcfg.h>
+
+struct link_map;
+
+extern void _dl_unmap (struct link_map *map);
+
+#define DL_UNMAP(map) _dl_unmap (map)