title: Brew won't upgrade on Mojave
body: <p>I have installed: </p>
  
  <ul>
  <li>Xcode 10</li>
  <li>Command Line Tools (macOS 10.14) for Xcode 10 Beta and Beta 2</li>
  <li><p>macOS_SDK_headers_for_macOS_10.14.pkg using this:</p>
  
  <pre><code>sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /
  </code></pre></li>
  </ul>
  
  <p>I have also opened Xcode 10 and waited for it to install components.</p>
  
  <p>Brew still gives me the error:</p>
  
  <pre><code>Error: The Command Line Tools header package must be installed on Mojave.
  The installer is located at:
  /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
  </code></pre>
  
  <p>Here is brew config</p>
  
  <pre><code>$ brew config
  HOMEBREW_VERSION: 1.6.12
  ORIGIN: https://github.com/Homebrew/brew
  HEAD: 0aab25bdb3bfa96d8eb14a38001ff6a24587bcdd
  Last commit: 8 hours ago
  Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
  Core tap HEAD: bde1292d5f98949e3f566b78c05e08bd30914afe
  Core tap last commit: 4 hours ago
  HOMEBREW_PREFIX: /usr/local
  CPU: quad-core 64-bit broadwell
  Homebrew Ruby: 2.3.7 =&gt; /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby
  Clang: 10.0 build 1000
  Git: 2.17.1 =&gt; /Applications/Xcode-beta.app/Contents/Developer/usr/bin/git
  Curl: 7.54.0 =&gt; /usr/bin/curl
  Java: N/A
  macOS: 10.14-x86_64
  CLT: 10.0.0.0.1.1527767617
  CLT headers: N/A
  Xcode: 10.0 =&gt; /Applications/Xcode-beta.app/Contents/Developer
  XQuartz: 2.7.11 =&gt; /opt/X11
  </code></pre>
  
  <p>What should I do next to get Brew to work?</p>