title: Unmarshal with global namespace
body: <p>I have the following XML:</p>
  
  <pre><code>&lt;rss version="2.0"&gt;
    &lt;channel&gt;
      ...
      &lt;item&gt;
        &lt;link&gt;http://stackoverflow.com&lt;/link&gt;
        &lt;atom:link xmlns:atom="http://www.w3.org/2005/Atom" href="http://stackoverflow.com"/&gt;
        ...
      &lt;/item&gt;
    &lt;/channel&gt;
  &lt;/rss&gt;
  </code></pre>
  
  <p>I want to extract the <code>link</code> attribute, I have the following struct:</p>
  
  <pre><code>type Item struct {
    Link string `xml:"http://www.w3.org/2005/Atom link"`
  }
  </code></pre>
  
  <p>I know, that I need a prefix to get the Link, but  because there is no namespace given (in form of an <code>xmls</code>-Attribute, but I don't know, how.</p>
  
  <p>I could, of course, save all <code>:*link</code>-Attributes to a slice, but I'm sure there is a better solution.</p>
  
  <p>Thanks in advance!</p>