Why does this simple std::thread example not work?

You have to join std::threads, just like you have to join pthreads.

int main( int argc, char *argv[] )
{
    std::thread t( doSomeWork );
    t.join();
    return 0;
}

UPDATE: This Debian bug report pointed me to the solution: add -pthread to your commandline. This is most probably a workaround until the std::thread code stabilizes and g++ pulls that library in when it should (or always, for C++).