From 2276736ceda992e7b9f0d2803445a33d712b0ce5 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Wed, 29 Jul 2020 19:12:24 +0100
Subject: [PATCH] Another try to configure <execution> correctly for libstdc++.

---
 include/boost/config/stdlib/libstdcpp3.hpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/boost/config/stdlib/libstdcpp3.hpp b/include/boost/config/stdlib/libstdcpp3.hpp
index b1466d9e..334c9074 100644
--- a/include/boost/config/stdlib/libstdcpp3.hpp
+++ b/include/boost/config/stdlib/libstdcpp3.hpp
@@ -324,9 +324,11 @@ extern "C" char *gets (char *__s);
 // unless these are installed seperately, including <execution> leads
 // to inscrutable errors inside libstdc++'s own headers.
 //
-#if !__has_include(<execution>) || (!__has_include(<tbb/blocked_range.h>) && !defined(_GLIBCXX_USE_TBB_PAR_BACKEND))
+#if (BOOST_LIBSTDCXX_VERSION < 100100)
+#if !__has_include(<tbb/tbb.h>)
 #define BOOST_NO_CXX17_HDR_EXECUTION
 #endif
+#endif
 #elif __cplusplus < 201402 || (BOOST_LIBSTDCXX_VERSION < 40900) || !defined(BOOST_LIBSTDCXX11)
 #  define BOOST_NO_CXX14_HDR_SHARED_MUTEX
 #endif