diff --git a/include/boost/config/stdlib/libstdcpp3.hpp b/include/boost/config/stdlib/libstdcpp3.hpp
index 163c4a7f..24126192 100644
--- a/include/boost/config/stdlib/libstdcpp3.hpp
+++ b/include/boost/config/stdlib/libstdcpp3.hpp
@@ -362,6 +362,18 @@ extern "C" char *gets (char *__s);
 #  define BOOST_NO_CXX20_HDR_COROUTINE
 #endif
 
+//
+// These next defines are mostly for older clang versions with a newer libstdc++ :
+//
+#if !defined(__cpp_lib_concepts)
+#if !defined(BOOST_NO_CXX20_HDR_COMPARE)
+#  define BOOST_NO_CXX20_HDR_COMPARE
+#endif
+#if !defined(BOOST_NO_CXX20_HDR_CONCEPTS)
+#  define BOOST_NO_CXX20_HDR_CONCEPTS
+#endif
+#endif
+
 //
 // Headers not present on Solaris with the Oracle compiler:
 #if defined(__SUNPRO_CC) && (__SUNPRO_CC < 0x5140)