PR libstdc++/91067 fix missing exports for filesystem iterators

The copy assignment operator for recursive_directory_iterator was not
exported despite being needed. The __shared_ptr default constructors are
not needed when compiling with GCC but Clang requires them for -O1.

	PR libstdc++/91067
	* acinclude.m4 (libtool_VERSION): Bump to 6:27:0.
	* configure: Regenerate.
	* config/abi/pre/gnu.ver (GLIBCXX_3.4.27): Add new version. Export
	missing symbols.
	* testsuite/27_io/filesystem/iterators/91067.cc: New test.
	* testsuite/util/testsuite_abi.cc: Add new symbol version.

From-SVN: r273023

1 files changed, 45 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/27_io/filesystem/iterators/91067.cc b/libstdc++-v3/testsuite/27_io/filesystem/iterators/91067.cc
new file mode 100644
index 00000000000..54172d9f20b
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/filesystem/iterators/91067.cc
@@ -0,0 +1,45 @@
+// Copyright (C) 2019 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.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do link { target c++17 } }
+// { dg-require-filesystem-ts "" }
+
+#include <filesystem>
+
+void
+test01()
+{
+  std::filesystem::directory_iterator d;
+  d = d;
+  d = std::move(d);
+}
+
+void
+test02()
+{
+  std::filesystem::recursive_directory_iterator d;
+  d = d;
+  d = std::move(d);
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}