diff --git a/include/boost/date_time/compiler_config.hpp b/include/boost/date_time/compiler_config.hpp
index 1b8c8f1..1041892 100644
--- a/include/boost/date_time/compiler_config.hpp
+++ b/include/boost/date_time/compiler_config.hpp
@@ -26,6 +26,12 @@
 #define BOOST_DATE_TIME_NO_MEMBER_INIT
 #endif
 
+//Include extensions to date_duration - comment out to remove this feature
+#define BOOST_DATE_TIME_OPTIONAL_GREGORIAN_TYPES
+//these extensions are known to cause problems with gcc295
+#if defined(__GNUC__) && (__GNUC__ < 3)
+#undef BOOST_DATE_TIME_OPTIONAL_GREGORIAN_TYPES
+#endif
 
 // include these types before we try to re-define them
 #include "boost/cstdint.hpp"