update boost on linux

linx64/include/boost/metaparse/v1/cpp11/impl/empty_string.hpp

@@ -0,0 +1,33 @@
+#ifndef BOOST_METAPARSE_V1_CPP11_IMPL_EMPTY_STRING_HPP
+#define BOOST_METAPARSE_V1_CPP11_IMPL_EMPTY_STRING_HPP
+
+// Copyright Abel Sinkovics (abel@sinkovics.hu)  2013.
+// Distributed under 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)
+
+namespace boost
+{
+  namespace metaparse
+  {
+    namespace v1
+    {
+      namespace impl
+      {
+        template <class Ignore = int>
+        struct empty_string
+        {
+          typedef empty_string type;
+
+          static constexpr char value[1] = {0};
+        };
+
+        template <class Ignore>
+        constexpr char empty_string<Ignore>::value[1];
+      }
+    }
+  }
+}
+
+#endif
+