clang + C++11 + libstdc++ compile errors

[viboes]

There are a lot of errors when compiling with clang on c++11 mode and linking with the default library libstdc++. The errors come from the fact that the code is expecting the standard library to provide some c++11 features which are missing, as std::forward.

clang-darwin.compile.c++ ../../../bin.v2/libs/test/test/class_properties_test.test/clang-darwin-3.1x/debug/class_properties_test.o
In file included from class_properties_test.cpp:17:
In file included from ../../../boost/test/unit_test.hpp:19:
In file included from ../../../boost/test/test_tools.hpp:373:
In file included from ../../../boost/test/tools/impl.hpp:25:
In file included from ../../../boost/test/tools/assertion.hpp:19:
../../../boost/test/utils/is_forward_iterable.hpp:72:26: error: no template named 'enable_if' in namespace 'std'; did you mean '__gnu_cxx::__enable_if'?
    static typename std::enable_if<
                    ~~~~~^~~~~~~~~
                         __gnu_cxx::__enable_if

See the attached file for a complete list of failures when running the libs/test tests.

[Gennadiy Rozental]

I believe clang compilation works fine now.