diff --git a/include/boost/system/detail/error_category_impl.hpp b/include/boost/system/detail/error_category_impl.hpp
index af93c1a..07101c1 100644
--- a/include/boost/system/detail/error_category_impl.hpp
+++ b/include/boost/system/detail/error_category_impl.hpp
@@ -108,7 +108,7 @@ inline error_category::operator std::error_category const & () const
     if( id_ == detail::generic_category_id )
     {
 // This condition must be the same as the one in error_condition.hpp
-#if defined(BOOST_GCC) && BOOST_GCC < 50000
+#if defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 50000
 
     static const boost::system::detail::std_category generic_instance( this, 0x1F4D3 );
     return generic_instance;
@@ -123,10 +123,12 @@ inline error_category::operator std::error_category const & () const
     if( id_ == detail::system_category_id )
     {
 // This condition must be the same as the one in error_code.hpp
-#if defined(__CYGWIN__) || defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER == 1800) || (defined(BOOST_GCC) && BOOST_GCC < 50000)
+#if defined(__CYGWIN__) || defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER == 1800) || (defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 90000)
 
     // Under Cygwin (and MinGW!), std::system_category() is POSIX
     // Under VS2013, std::system_category() isn't quite right
+    // Under libstdc++ before 7.4, before 8.3, before 9.1, default_error_condition
+    // for the system category returns a condition from the system category
 
     static const boost::system::detail::std_category system_instance( this, 0x1F4D7 );
     return system_instance;
diff --git a/include/boost/system/detail/error_code.hpp b/include/boost/system/detail/error_code.hpp
index 1cd01e6..f7d9d30 100644
--- a/include/boost/system/detail/error_code.hpp
+++ b/include/boost/system/detail/error_code.hpp
@@ -575,7 +575,7 @@ public:
         else if( lc_flags_ == 0 )
         {
 // This condition must be the same as the one in error_category_impl.hpp
-#if defined(__CYGWIN__) || defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER == 1800) || (defined(BOOST_GCC) && BOOST_GCC < 50000)
+#if defined(__CYGWIN__) || defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER == 1800) || (defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 90000)
 
             return std::error_code( 0, boost::system::system_category() );
 
diff --git a/include/boost/system/detail/error_condition.hpp b/include/boost/system/detail/error_condition.hpp
index 255b282..b54498b 100644
--- a/include/boost/system/detail/error_condition.hpp
+++ b/include/boost/system/detail/error_condition.hpp
@@ -223,7 +223,7 @@ public:
     operator std::error_condition () const
     {
 // This condition must be the same as the one in error_category_impl.hpp
-#if defined(BOOST_GCC) && BOOST_GCC < 50000
+#if defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 50000
 
         return std::error_condition( value(), category() );