From ac042ab93db179d98f3b742ff893032e77326417 Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Tue, 20 Oct 2015 07:37:11 +0000
Subject: [PATCH] Detect relaxed constexpr rules for gcc versions

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@250802 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/__config | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/__config b/include/__config
index bc01805f7..b7e353272 100644
--- a/include/__config
+++ b/include/__config
@@ -451,8 +451,11 @@ namespace std {
 #define _LIBCPP_HAS_NO_CONSTEXPR
 #endif
 
-// No version of GCC supports relaxed constexpr rules
+// Determine if GCC supports relaxed constexpr
+#if !defined(__cpp_constexpr) || __cpp_constexpr < 201304L
 #define _LIBCPP_HAS_NO_CXX14_CONSTEXPR
+#endif
+
 // GCC 5 will support variable templates
 #define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES