When running "g++ -std=c++0x" on the following two lines,

  std::wstring s;
  s = std::wstring(L"hello world");

the loader complains that there is an
undefined reference to `std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::operator=(std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >&&)'

However, if the file x86_64-unknown-linux-gnu/libstdc++-v3/src/wstring-inst.o
in the gcc 4.5.0 build directory is added to the loader line, then there is
no problem.