title: PHP http_build_query() generate incorrect url for array get parameter
body: <p>I probably discovered a bug of a PHP function http_build_query().</p>
  
  <p>I am developing a search engine with dynamic form and some of these parameters are array.</p>
  
  <p>I simply get the query url from the current $_GET with http_build_query().
  But all of these array parameters are <strong>automatically changed from "arrayName%5B%5D" to "arrayName%5B0%5D"</strong> in the new query generated.</p>
  
  <pre><code>$queryStr = http_build_query($_GET);
  </code></pre>
  
  <blockquote>
    <p><strong>original url</strong></p>
    
    <p>&amp;arrayName%5B%5D=</p>
    
    <p><strong>new query string got from http_build_query():</strong></p>
    
    <p>&amp;arrayName%5B<strong>0</strong>%5D=</p>
  </blockquote>
  
  <p><strong>What is the reason for this? How to fix this?</strong></p>