title: g++ 4.6 issue no <bits/c++config.h> file as required by the header cstring
body: <p>There is no file called <code>bits/c++config.h</code> in the c++ include directory which is required by the <code>cstring</code> header file. But when I include the the header <code>cstring</code> and compile with <code>g++</code>, it does not give me error. The problem occurred when I tried to compile the program with <code>clang++</code>  compiler in the following way.</p>
  
  <pre><code>$clang++ -cc1 -I/usr/include -I/usr/include/c++/4.6.1 -I/usr/lib/gcc/i686-linux-gnu/4.6.1 -I/usr/include/i386-linux-gnu -I opt_149739_build/include hello.cpp
  
  In file included from /media/space/hello.cpp:2:
  In file included from /media/space/opt_149739_build/include/clang/Driver/Driver.h:13:
  In file included from /media/space/opt_149739_build/include/clang/Basic/Diagnostic.h:17:
  In file included from /media/space/opt_149739_build/include/clang/Basic/DiagnosticIDs.h:18:
  In file included from /media/space/opt_149739_build/include/llvm/ADT/StringRef.h:14:
  /usr/include/c++/4.6.1/cstring:42:10: fatal error: 'bits/c++config.h' file not found
  #include &lt;bits/c++config.h&gt;
  </code></pre>
  
  <p>I am using g++ 4.6.1 on Ubuntu 11.04</p>
  
  <p>What went wrong?</p>