title: composer dependency stating it doesn't have php-xsl
body: <p>A composer dependency is stating it doesn't have php-xsl. I'm trying to install phpdocumentor/phpdocumentor, but it won't let me because of a requirement. So now I'm trying to install the requirement and I get this:</p>
  
  <pre><code>$ composer require phpdocumentor/template-zend
  Using version ~1.3 for phpdocumentor/template-zend
  ./composer.json has been updated
  Loading composer repositories with package information
  Updating dependencies (including require-dev)
  Your requirements could not be resolved to an installable set of packages.
  
    Problem 1
      - phpdocumentor/template-zend 1.3.2 requires ext-xsl * -&gt; the requested PHP extension xsl is missing from your system.
      - phpdocumentor/template-zend 1.3.1 requires ext-xsl * -&gt; the requested PHP extension xsl is missing from your system.
      - phpdocumentor/template-zend 1.3.0 requires ext-xsl * -&gt; the requested PHP extension xsl is missing from your system.
      - Installation request for phpdocumentor/template-zend ~1.3 -&gt; satisfiable by phpdocumentor/template-zend[1.3.0, 1.3.1, 1.3.2].
  
  
  Installation failed, reverting ./composer.json to its original content.
  </code></pre>
  
  <p>PHP info:</p>
  
  <pre><code>xsl
  
  XSL enabled
  libxslt Version 1.1.28
  libxslt compiled against libxml Version 2.9.1
  EXSLT   enabled
  libexslt Version    1.1.28
  </code></pre>
  
  <p>Or is it maybe telling me I need ext-xsl?  What is that? Or is it saying what it looks like to me, that I need PHP xsl?</p>
  
  <p>This is different that the marked dup post, see my comment below as to why.</p>