Use of undefined constant LIBXML_HTML_NOIMPLIED
<p>I have just deployed some DOM Manipulation code to our staging server and am getting the error:</p>

<pre><code>[PHP notice] Use of undefined constant LIBXML_HTML_NOIMPLIED - assumed 'LIBXML_HTML_NOIMPLIED'
</code></pre>

<p>I have no issues on my desktop using WAMP and cannot find any modules that appear to be related.</p>

<p>Our Centos 6 server appears to be using PHP version 5.4.34 with libxml2-2.7.6-1 installed.</p>

<p>I have searched our <code>php.ini</code> file and there is no mention of 'libxml' and <code>phpinfo()</code> gives me the following section for lib_xml:</p>

<pre><code>libxml

libXML support =&gt; active
libXML Compiled Version =&gt; 2.7.6
libXML Loaded Version =&gt; 20706
libXML streams =&gt; enabled
</code></pre>

<p>Why would this constant be undefined?</p>