zendframework/zendframework#6785 - using is_subclass_of() instead o…

…f protected static method usage

See bug https://bugs.php.net/bug.php?id=53727
See bug zendframework/zendframework#1807

Deprecating protected static polyfill method `isSubclassOf`

src/AutoloaderFactory.php

@@ -86,7 +86,7 @@ public static function factory($options = null)
                     );
                 }
 
-                if (!static::isSubclassOf($class, 'Zend\Loader\SplAutoloader')) {
+                if (!is_subclass_of($class, 'Zend\Loader\SplAutoloader')) {
                     require_once 'Exception/InvalidArgumentException.php';
                     throw new Exception\InvalidArgumentException(
                         sprintf('Autoloader class %s must implement Zend\\Loader\\SplAutoloader', $class)
@@ -198,6 +198,8 @@ protected static function getStandardAutoloader()
      * @see https://bugs.php.net/bug.php?id=53727
      * @see https://github.com/zendframework/zf2/pull/1807
      *
+     * @deprecated since zf 2.3 requires PHP >= 5.3.23
+     *
      * @param  string $className
      * @param  string $type
      * @return bool