Fix incorrect __cpp_lib_parallel_algorithm macro definitions

	* include/std/algorithm (__cpp_lib_parallel_algorithm): Fix value.
	* include/std/memory (__cpp_lib_parallel_algorithm): Likewise.
	* include/std/numeric (__cpp_lib_parallel_algorithm): Likewise.
	* testsuite/25_algorithms/pstl/feature_test.cc: New test.

From-SVN: r272216

libstdc++-v3/ChangeLog

 2019-06-12  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/algorithm (__cpp_lib_parallel_algorithm): Fix value.
+	* include/std/memory (__cpp_lib_parallel_algorithm): Likewise.
+	* include/std/numeric (__cpp_lib_parallel_algorithm): Likewise.
+	* testsuite/25_algorithms/pstl/feature_test.cc: New test.
+
 	* include/std/variant (get<T>, get<N>, get_if<N>, get_if<T>)
 	(variant::emplace): Change static_assert messages from "should be"
 	to "must be".

libstdc++-v3/include/std/algorithm

@@ -73,7 +73,7 @@
 #  endif
 
 // Feature test macro for parallel algorithms
-# define __cpp_lib_parallel_algorithm 201703L
+# define __cpp_lib_parallel_algorithm 201603L
 #endif // C++17
 
 #ifdef _GLIBCXX_PARALLEL

libstdc++-v3/include/std/memory

@@ -407,7 +407,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
 # endif
 
 // Feature test macro for parallel algorithms
-# define __cpp_lib_parallel_algorithm 201703L
+# define __cpp_lib_parallel_algorithm 201603L
 #endif // C++17
 
 #endif /* _GLIBCXX_MEMORY */

libstdc++-v3/include/std/numeric

@@ -216,7 +216,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
 # endif
 
 // Feature test macro for parallel algorithms
-# define __cpp_lib_parallel_algorithm 201703L
+# define __cpp_lib_parallel_algorithm 201603L
 #endif // C++17
 
 #endif /* _GLIBCXX_NUMERIC */

libstdc++-v3/testsuite/25_algorithms/pstl/feature_test.cc

+// 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 preprocess { target c++17 } }
+
+#include <algorithm>
+#ifndef __cpp_lib_parallel_algorithm
+# error "Feature-test macro for parallel algorithms missing"
+#elif __cpp_lib_parallel_algorithm != 201603L
+# error "Feature-test macro for parallel algorithms has wrong value in <algorithm>"
+#endif
+
+#include <numeric>
+#if __cpp_lib_parallel_algorithm != 201603L
+# error "Feature-test macro for parallel algorithms has wrong value in <numeric>"
+#endif
+
+#include <version>
+#if __cpp_lib_parallel_algorithm != 201603L
+# error "Feature-test macro for parallel algorithms has wrong value in <version>"
+#endif
+
+// The N4810 draft does not require the macro to be defined in <execution>.
+#include <memory>
+#if __cpp_lib_parallel_algorithm != 201603L
+# error "Feature-test macro for parallel algorithms has wrong value in <memory>"
+#endif
+
+// The N4810 draft does not require the macro to be defined in <execution>.
+// Include this last, because it will trigger the inclusion of TBB headers,
+// which then include <memory>, so we need to have already checked <memory>.
+#include <execution>
+#if __cpp_lib_parallel_algorithm != 201603L
+# error "Feature-test macro for parallel algorithms has wrong value in <execution>"
+#endif