Added emplace(void) for older compilers

test/Jamfile.v2

@@ -1,15 +1,16 @@
-#  Boost.Optional Library test Jamfile
+# Boost.Optional Library test Jamfile
 #
-#  Copyright (C) 2003, Fernando Luis Cacciola Carballal.
+# Copyright (C) 2003, Fernando Luis Cacciola Carballal.
+# Copyright (C) 2014, 2015 Andrzej Krzemienski
 #
-#  This material is provided "as is", with absolutely no warranty expressed
-#  or implied. Any use is at your own risk.
+# Use, modification, and distribution is 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)
 #
-#  Permission to use or copy this software for any purpose is hereby granted
-#  without fee, provided the above notices are retained on all copies.
-#  Permission to modify the code and to distribute modified code is granted,
-#  provided the above notices are retained, and a notice that the code was
-#  modified is included with the above copyright notice.
+# See http://www.boost.org/libs/optional for documentation.
+#
+# You are welcome to contact the author at:
+#  akrzemi1@gmail.com
 #
 
 import testing ;

test/optional_test_emplace.cpp

@@ -145,11 +145,16 @@ void test_clear_on_throw()
 
 void test_no_assignment_on_emplacement()
 {
-    optional<const std::string> os;
+    optional<const std::string> os, ot;
     BOOST_TEST(!os);
     os.emplace("wow");
     BOOST_TEST(os);
     BOOST_TEST_EQ(*os, "wow");
+    
+    BOOST_TEST(!ot);
+    ot.emplace();
+    BOOST_TEST(ot);
+    BOOST_TEST_EQ(*ot, "");
 }
 
 int main()

test/optional_test_swap.cpp

@@ -15,6 +15,7 @@
 //
 
 #include "boost/optional/optional.hpp"
+#include "boost/utility/in_place_factory.hpp"
 
 #ifdef __BORLANDC__
 #pragma hdrstop