title: "iostream" file not found in Xcode 4.2
body: <p>I'm adding Zxing 1.7(Qr scanner) to my projects.</p>
  
  <p>I upgraded Mac OS X to Lion and xcode4.2, iOS5.0.</p>
  
  <p>Problem is that when I run the project, I always saw "iostream file not found".</p>
  
  <p>I run the scanTest(Qr scanner test sample code prvided from Zxing team) ,but it works well.</p>
  
  <p>So, I compare my projects and scanTest, but I can't find any difference.</p>
  
  <p>What can I do to solve this problem?</p>