merging intrusive from develop

Jamfile

@@ -0,0 +1,11 @@
+#  Boost.Intrusive Library Jamfile
+#
+#  Copyright (c) 2018 Ion Gaztanaga
+#
+#  Use, modification, and distribution are subject to the
+#  Boost Software License, Version 1.0. (See accompanying file
+#  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+# please order by name to ease maintenance
+build-project example ;
+build-project test ;

include/boost/intrusive/pointer_plus_bits.hpp

@@ -30,6 +30,9 @@
 #  if (BOOST_GCC >= 40600)
 #     pragma GCC diagnostic push
 #     pragma GCC diagnostic ignored "-Wuninitialized"
+#     if (BOOST_GCC >= 40700)
+#        pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#     endif
 #  endif
 #endif