diff --git a/include/boost/config/select_stdlib_config.hpp b/include/boost/config/select_stdlib_config.hpp
index 9c970667..2a1430ae 100644
--- a/include/boost/config/select_stdlib_config.hpp
+++ b/include/boost/config/select_stdlib_config.hpp
@@ -40,7 +40,7 @@
 // Rogue Wave library:
 #  define BOOST_STDLIB_CONFIG "boost/config/stdlib/roguewave.hpp"
 
-#elif defined(__GLIBCPP__) || defined(__GLIBCXX__) || defined(_GLIBCXX_CSTDDEF)
+#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
 // GNU libstdc++ 3
 #  define BOOST_STDLIB_CONFIG "boost/config/stdlib/libstdcpp3.hpp"