title: experimental::filesystem linker error
body: <p>I try to use the new c++1z features actually on the head of development within gcc 6.0.</p>
  
  <p>If I try this little example:</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;experimental/filesystem&gt;
  namespace fs = std::experimental::filesystem;
  int main()
  {
      fs::path p1 = "/home/pete/checkit";
  
      std::cout &lt;&lt; "p1 = " &lt;&lt; p1 &lt;&lt; std::endl;
  }
  </code></pre>
  
  <p>I got:</p>
  
  <pre>
  /opt/linux-gnu_6-20151011/bin/g++ --std=c++1z main.cpp -O2 -g -o go
  /tmp/ccaGzqFO.o: In function \`std::experimental::filesystem::v1::__cxx11::path::path(char const (&) [36])':
  /opt/linux-gnu_6-20151011/include/c++/6.0.0/experimental/bits/fs_path.h:167: undefined reference to `std::experimental::filesystem::v1::__cxx11::path::_M_split_cmpts()'
  collect2: error: ld returned 1 exit status
  </pre>
  
  <p>gcc version is the snapshot linux-gnu_6-20151011</p>
  
  <p>Any hints how to link for the new c++1z features?</p>