title: Homebrew aspell directory not writable
body: <p>I am having some difficulties. This started with a broader question but I seem (with some help from this list) to have narrowed things down a bit. My original query is at <a href="https://stackoverflow.com/questions/53272141/emacs-kieran-healys-emacs-starter-kit-aspell-english-dictionery">Emacs - Kieran Healy&#39;s Emacs Starter Kit aspell English dictionery</a></p>
  
  <p>(And, yes, I am embarrassed at the spelling error in the title). </p>
  
  <p>I have narrowed (with some help from that question) to narrow my problem down to the Homebrew installation of aspell. The command <code>brew install aspell</code> gives the following error. </p>
  
  <pre><code>Error: The `brew link` step did not complete successfully
  The formula built, but is not symlinked into /usr/local
  Could not symlink lib/aspell-0.60/american-variant_0.alias
  /usr/local/lib/aspell-0.60 is not writable.
  
  You can try again using:
  brew link aspell
  </code></pre>
  
  <p>If I try <code>brew link aspell</code> I get the following error:</p>
  
  <pre><code>Linking /usr/local/Cellar/aspell/0.60.6.1_1... 
  Error: Could not symlink lib/aspell-0.60/american-variant_0.alias
  /usr/local/lib/aspell-0.60 is not writable.
  </code></pre>
  
  <p>File permissions on aspell are</p>
  
  <pre><code>drwxr-xr-x  89 root  wheel  2848  7 Nov  2016 aspell-0.60
  </code></pre>
  
  <p><code>brew doctor</code> gives</p>
  
  <pre><code>Warning: You have unlinked kegs in your Cellar
  Leaving kegs unlinked can lead to build-trouble and cause brews that 
  depend on
  those kegs to fail to run properly once built. Run `brew link` on 
  these:
  aspell
  </code></pre>
  
  <p>It also tells me I need to update from XCode 9.3 to XCode 10.1, but since I am still running MacOS 10.13.4, I think I do not need to do this. </p>
  
  <p>Any help greatly appreciated. </p>