add string_ref to list of enabled features

when outputting systemtap versions (stap -V), output BOOST_STRING_REF
in the list enabled features

diff --git a/session.cxx b/session.cxx
index 55f8e184b2de155cbccee26660aa7894a19c9e57..1a979ba389276e39a955f7acfd5cc4dc11369052 100644 (file)
--- a/session.cxx
+++ b/session.cxx
@@ -492,6 +492,9 @@ systemtap_session::version ()
 #endif
 #ifdef HAVE_LIBXML2
        << " LIBXML2"
+#endif
+#ifdef HAVE_BOOST_UTILITY_STRING_REF_HPP
+       << " BOOST_STRING_REF"
 #endif
        << endl;
 }