title: How do I fix 'brew install pkg-config'?
body: <pre><code>Warning: Could not link pkg-config. Unlinking...
  Error: The `brew link` step did not complete successfully
  The formula built, but is not symlinked into /usr/local
  You can try again using `brew link pkg-config`‏‏‏‏‏‏
  </code></pre>