From 4d986730982c3b213f3047dc2405ce003e899d6d Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Fri, 5 Mar 2021 16:18:05 +0000
Subject: [PATCH] Correct macro spelling.

---
 include/boost/config/stdlib/libcpp.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/boost/config/stdlib/libcpp.hpp b/include/boost/config/stdlib/libcpp.hpp
index 1d824a73..c7daab1f 100644
--- a/include/boost/config/stdlib/libcpp.hpp
+++ b/include/boost/config/stdlib/libcpp.hpp
@@ -158,9 +158,9 @@
 #  define BOOST_NO_CXX20_HDR_SEMAPHORE
 #endif
 
-# if(_LIBCPP_VERSION < 9000) && !defined(BOOST_NO_CXX20_HDR_SOURCE_SPAN)
+#if(_LIBCPP_VERSION < 9000) && !defined(BOOST_NO_CXX20_HDR_SPAN)
 // as_writable_bytes is missing.
-#  define BOOST_NO_CXX20_HDR_SOURCE_SPAN
+#  define BOOST_NO_CXX20_HDR_SPAN
 #endif
 
 #else