title: fatal error: 'vector' file not found, with Xcode 10
body: <p>I seem to be having an issue with macOS SDK headers on the command line after upgrading to Xcode 10. I know Apple added <code>macOS_SDK_headers_for_macOS_10.14.pkg</code> in <code>/Library/Developer/CommandLineTools/Packages</code>, which I have installed - but unfortunately that doesn't seem to have helped. Are there any other changes in Xcode 10 I may have missed?</p>
  
  <p>Here is the log:</p>
  
  <pre><code>20:54.19 In file included from /Users/&lt;user&gt;/Workspace/modules/brotli/enc/backward_references.cc:9:
  20:54.19 /Users/&lt;user&gt;/Workspace/modules/brotli/enc/./backward_references.h:12:10: fatal error: 'vector' file not found
  20:54.19 #include &lt;vector&gt;
  20:54.19          ^~~~~~~~
  20:54.23 1 error generated.
  20:54.23 make[5]: *** [host_backward_references.o] Error 1
  20:54.23 make[4]: *** [modules/brotli/host] Error 2
  20:54.23 make[4]: *** Waiting for unfinished jobs....
  </code></pre>