--- /dev/null
+++ b/library/vendor/HTMLPurifier.autoload-legacy.php
@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * @file
+ * Legacy autoloader for systems lacking spl_autoload_register
+ *
+ * Must be separate to prevent deprecation warning on PHP 7.2
+ */
+
+function __autoload($class)
+{
+    return HTMLPurifier_Bootstrap::autoload($class);
+}
+
+// vim: et sw=4 sts=4
--- a/library/vendor/HTMLPurifier.autoload.php
+++ b/library/vendor/HTMLPurifier.autoload.php
@@ -14,10 +14,7 @@
         spl_autoload_register('__autoload');
     }
 } elseif (!function_exists('__autoload')) {
-    function __autoload($class)
-    {
-        return HTMLPurifier_Bootstrap::autoload($class);
-    }
+    require dirname(__FILE__) . '/HTMLPurifier.autoload-legacy.php';
 }
 
 if (ini_get('zend.ze1_compatibility_mode')) {