libstdc++/77795 Only declare ::gets for C++98 and C++11

	PR libstdc++/77795
	* acinclude.m4 (GLIBCXX_CHECK_STDIO_PROTO): Use -std=gnu++11 to check
	for gets.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/c_global/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Only declare
	for C++98 and C++11.
	* include/c_std/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Likewise.
	* testsuite/27_io/headers/cstdio/functions_neg.cc: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240672 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 25 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc b/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc
new file mode 100644
index 00000000000..f9e5f86ed37
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc
@@ -0,0 +1,25 @@
+// { dg-do compile  { target c++14 } }
+
+// Copyright (C) 2007-2016 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/>.
+
+#include <cstdio>
+
+namespace gnu
+{
+  using std::gets; // { dg-error "has not been declared" }
+}