Undefined symbols for architecture x86_64:
  "print_message(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
      _main in test-cbae7a.o
  "std::ostream::operator<<(std::ostream& (*)(std::ostream&))", referenced from:
      print_message(std::string const&) in print.o
  "std::ios_base::Init::Init()", referenced from:
      ___cxx_global_var_init in print.o
  "std::ios_base::Init::~Init()", referenced from:
      ___cxx_global_var_init in print.o
  "std::cout", referenced from:
      print_message(std::string const&) in print.o
  "std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
      print_message(std::string const&) in print.o
  "std::basic_ostream<char, std::char_traits<char> >& std::operator<<<char, std::char_traits<char>, std::allocator<char> >(std::basic_ostream<char, std::char_traits<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)", referenced from:
      print_message(std::string const&) in print.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)