title: Issue with std::thread from c++11
body: <p>I have some troubles trying to compile a program with multi-threading from the standard template library.
  It return me a obscure error when i try to compile the following program :</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;thread&gt;
  
  void foo()
  {
      std::cout &lt;&lt; "Thread 1\n";
  }
  
  int main(int argc, char** argv)
  {
      std::thread tr(foo);
      std::cout &lt;&lt; "Main thread\n";
      tr.join();
  
      return 0;
  }
  </code></pre>
  
  <p>I don't understand the error : </p>
  
  <pre><code>/tmp/ccE8EtL1.o : In the function « std::thread::thread&lt;void (&amp;)()&gt;(void (&amp;)()) » :
   file.cpp:(.text._ZNSt6threadC2IRFvvEJEEEOT_DpOT0_[_ZNSt6threadC5IRFvvEJEEEOT_DpOT0_]+0x21) : undefined reference to « pthread_create »
    collect2: error : ld has return 1 execution status code
  </code></pre>
  
  <p>I compile it with :</p>
  
  <blockquote>
    <p>g++ -std=c++14 file.cpp -o test -Wall</p>
  </blockquote>
  
  <p>Can anyone help me please ?</p>