From 08370c91581dbfa8ea301d28765c881e0682f68a Mon Sep 17 00:00:00 2001
From: Thomas Barbier <thomas.barbier@amadeus.com>
Date: Tue, 1 Oct 2019 18:49:31 +0200
Subject: [PATCH] Fix c++17 warning redundant redeclaration of 'constexpr'
 static data member [-Werror=deprecated]

---
 include/boost/system/error_code.hpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/boost/system/error_code.hpp b/include/boost/system/error_code.hpp
index f0a151e..9fb7de3 100644
--- a/include/boost/system/error_code.hpp
+++ b/include/boost/system/error_code.hpp
@@ -335,8 +335,11 @@ template<class T> struct BOOST_SYMBOL_VISIBLE cat_holder
     static constexpr generic_error_category generic_category_instance{};
 };
 
+// Before C++17 it was mandatory to redeclare all static constexpr
+#if defined(BOOST_NO_CXX17_INLINE_VARIABLES)
 template<class T> constexpr system_error_category cat_holder<T>::system_category_instance;
 template<class T> constexpr generic_error_category cat_holder<T>::generic_category_instance;
+#endif
 
 } // namespace detail