title: Installing libmxl2 into virtual environment OSX
body: <p>I've already read the questions <a href="https://stackoverflow.com/questions/13019942/why-cant-i-get-pip-install-lxml-to-work-within-a-virtualenv">here</a>, <a href="https://stackoverflow.com/questions/3856468/how-to-install-libxml2-in-virtualenv">here</a> and <a href="https://stackoverflow.com/questions/26473197/how-to-install-libxml2-dev-libxslt-dev-on-mac-os">here</a>.  Basically, I'm using a conda environment and I want to install <code>lxml</code>.  When I run <code>pip install lxml</code> I get a long error message that includes <code>Failed building wheel for lxml</code> and <code>error minimum required version of libxslt is 1.1.23</code>.  This makes me believe I need to install <code>libxml2</code> and <code>libxslt</code> into the virtual environment (they are already installed on the system <em>outside</em> the environment.)  </p>
  
  <p>So for Linux, I read in one of the linked answers that I should run:</p>
  
  <pre><code>apt-get install libxml2-dev libxslt-dev
  </code></pre>
  
  <p>I tried to adapt that to OSX and homebrew.  Inside the conda environment I ran:</p>
  
  <pre><code>brew install libxml2-dev libxslt-dev
  </code></pre>
  
  <p>and got:</p>
  
  <pre><code>Error: No available formula with the name "libxml2-dev"
  </code></pre>
  
  <p>How do I get homebrew to install <code>libxml2</code> into the conda environment?</p>