From 57d26f5ab3ad00c36bf7573f906e1d455422ca22 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Sat, 12 Feb 2022 20:48:46 +0200
Subject: [PATCH] libstdc++ 4.8 and below don't have std::bit_not. Fixes #28.

---
 include/boost/bind/detail/result_traits.hpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/boost/bind/detail/result_traits.hpp b/include/boost/bind/detail/result_traits.hpp
index dedc668..f8de9cd 100644
--- a/include/boost/bind/detail/result_traits.hpp
+++ b/include/boost/bind/detail/result_traits.hpp
@@ -142,6 +142,12 @@ template<class T> struct result_traits< unspecified, std::bit_xor<T> >
     typedef T type;
 };
 
+#if defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 40900
+
+// libstdc++ 4.8 and below don't have std::bit_not
+
+#else
+
 template<class T> struct result_traits< unspecified, std::bit_not<T> >
 {
     typedef T type;
@@ -149,6 +155,8 @@ template<class T> struct result_traits< unspecified, std::bit_not<T> >
 
 #endif
 
+#endif
+
 } // namespace _bi
 
 } // namespace boost