diff --git a/src/stl_port.cpp b/src/stl_port.cpp
index 298cdfa0..e5378bca 100644
--- a/src/stl_port.cpp
+++ b/src/stl_port.cpp
@@ -18,8 +18,7 @@
 
 #include <boost/config.hpp>
 
-#if defined(__SGI_STL_PORT) 
-#if defined(_STLPORT_VERSION) && (_STLPORT_VERSION < 0x500)
+#if defined(__SGI_STL_PORT) && (__SGI_STL_PORT < 0x500)
 
 #include <boost/archive/codecvt_null.hpp>
 
@@ -39,7 +38,6 @@ locale::locale(
 
 } // namespace std
 
-#endif
 #endif
 
 #endif