title: Eigen3 exit code 127 on formatted string output
body: <pre><code>MatrixXd p(10,10);
  // set values of p
  
  // for loop prints out all values of p
  for (int i = 0; i &lt; 100; i++)
    std::cout &lt;&lt; p(i/10,i%10) &lt;&lt; std::endl;
  
  
  const IOFormat CleanFmt(4,0,", ","\n","[","]");
  std::cout &lt;&lt; p.format(CleanFmt);
  // fails before running any code with error 1 (cxx = 20)
  // fails before running any code with error 127 (cxx = 14/11)
  </code></pre>
  
  <p>Having trouble debugging this, as it is failing outright.  My OS setup is Cygwin in Windows. Perhaps it is failing since windows does not support FIFO-Qs? </p>
  
  <p>Or is something wrong going on here?</p>