title: Strange use of undeclared identifier in mmintrin.h clang error
body: <p>I am trying to build my app for my device and am including the <code>libosmscout</code> library. Strangely, one of Apple's headers is giving me a load of errors:</p>
  
  <pre><code>/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/7.3.0/include/mmintrin.h:39:5: Use of undeclared identifier '__builtin_ia32_emms'; did you mean '__builtin_isless'?
  
  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/7.3.0/include/mmintrin.h:39:25: Too few arguments to function call, expected 2, have 0
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/8kiSU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8kiSU.png" alt="enter image description here"></a></p>
  
  <p>I don't understand why is going wrong here. Where does the <code>mmintrin.h</code> file come from? Could I be missing an include somewhere? It appears to be a clang error.</p>