title: How to use include-what-you-use on Debian 8.5
body: <p>I'm trying to use include-what-you-use on Debian 8.5.  I made a test program that simply includes <code>&lt;iostream&gt;</code> and std::cout's "Hello, world" to the terminal.  When I invoke <code>iwyu</code> on it, I get the following:</p>
  
  <blockquote>
    <p>t1.cpp:1:10: fatal error: 'iostream' file not found</p>
  </blockquote>
  
  <p>Clearly it can't seem to locate the system headers.  I suppose I can force it by using the <code>-I</code> option, but I feel as though I shouldn't have to do that.  Requiring me to tell it where the system headers are leads me to believe that something else is horribly wrong and using <code>-I</code> is just treating the symptom and not the cause.</p>
  
  <p>Incidently, I have verified that invoking clang to compile my test program works just fine.  So clang itself seems to work.</p>
  
  <p>Thanks in advance!</p>