title: Clang errors after deletion in /usr/bin and copying back
body: <p>Please don't ask me what on earth got into me deleting <code>clang</code> from the <code>/usr/bin</code> folder...I got weird error messages and couldn't find anything on the web...</p>
  
  <p>However, I deleted <code>clang</code>, tried reinstalling Xcode + developer tools, but <code>clang</code> wasn't installed again. So I searched inside the Xcode folder and found it in <code>/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang</code> </p>
  
  <p>So, I copied this (and <code>clang++</code>) back to my <code>/usr/bin</code> folder, but now I'm getting weird error messages again, e.g:</p>
  
  <pre><code>fatal error: 'stdarg.h' file not found
  #include &lt;stdarg.h&gt;
           ^
  1 error generated.
  </code></pre>
  
  <p>Any idea how I could fix this?</p>