title: BOOST_PP_ITERATE() result in "no such file or directory"
body: <p>I'm learning the boost preprocessor library (because i need to use it), and I wanted to try the file iteration mechanism. I've set up a minimal project with a.cpp and b.hpp. What I'm trying to do is including many time b.hpp via the boost pp :</p>
  
  <pre><code>#include &lt;boost/preprocessor/iteration/iterate.hpp&gt;
  
  #define BOOST_PP_ITERATION_LIMITS (0, 5)
  #define BOOST_PP_FILENAME_1 "b.hpp"
  #include BOOST_PP_ITERATE()
  </code></pre>
  
  <p>When I try to compile (with -E to see the preprocessor result) :</p>
  
  <pre><code>g++ -E a.cpp &gt; pp_result
  </code></pre>
  
  <p>I got this error :</p>
  
  <blockquote>
    <p>In file included from a.cpp:
    /usr/local/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:47:37: error: b.hpp: No such file or directory</p>
  </blockquote>
  
  <p>b.hpp is in the same directory, I can't see what I'm dooing wrong. It seems the g++ searches b.hpp in the same directory as forward1.hpp, but following the boost documentation my code should work (my boost version is 1.44).</p>
  
  <p>Does anybody experienced the same problem ?</p>