title: Big Sur clang "invalid version" error due to MACOSX_DEPLOYMENT_TARGET
body: <p>I assume due to the fact Big Sur is sparkling new hotfixes for the new OS have not yet happen. When attempting to install modules that use <code>clang</code> for compilation, the following error is thrown:</p>
  <pre><code>clang: error: invalid version number in 'MACOSX_DEPLOYMENT_TARGET=11.0'
  </code></pre>
  <p>Currently running:</p>
  <ul>
  <li>Mac OS Big Sur, 11.0 Beta</li>
  <li><strong>Intel</strong> CPU (i386)</li>
  <li>Python 3.8.0 installed via <code>pyenv</code></li>
  </ul>
  <p>Multiple modules have <code>clang</code> dependencies, and so it seems this error is quite common. An example:</p>
  <pre><code>pip install multidict
  </code></pre>
  <p>Installing older versions of Command Line Tools (e.g. 11.5) does not work as well.</p>