Smarty Compat

<?php
    /**
     * Merges two arrays recursively and "binary safe" (integer keys are
     * overridden as well), overruling similar values in the first array
     * ($arr0) with the values of the second array ($arr1)
     * In case of identical keys, ie. keeping the values of the second.
     *
     * @param array   $arr0       First array
     * @param array   $arr1       Second array, overruling the first array
     * @param boolean $notAddKeys If set, keys that are NOT found in $arr0 (first array) will not be set.
     * Thus only existing value can/will be overruled from second array.
     * @param boolean $includeEmptyValues If set, values from $arr1 will overrule if they are
     * empty or zero. Default: TRUE
     * @param boolean $enableUnsetFeature If set, special values "__UNSET" can be used in the second array
     * in order to unset array keys in the resulting array.
     * @return array Resulting array where $arr1 values has overruled $arr0 values
     */
    public static function arrayMergeRecursiveOverrule(
        array $arr0,
        array $arr1,
        $notAddKeys = false,
        $includeEmptyValues = true,
        $enableUnsetFeature = true
    ) {
        if (class_exists('\TYPO3\CMS\Core\Utility\GeneralUtility')) {
            if (method_exists('\TYPO3\CMS\Core\Utility\ArrayUtility', 'mergeRecursiveWithOverrule')) {
                call_user_func_array(
                    array('\TYPO3\CMS\Core\Utility\ArrayUtility', 'mergeRecursiveWithOverrule'),
                    array(
                        &$arr0,
                        $arr1,
                        $notAddKeys,
                        $includeEmptyValues,
                        $enableUnsetFeature
                    )
                );
                return $arr0;
            } else {
                return call_user_func(
                    array('\TYPO3\CMS\Core\Utility\GeneralUtility', 'array_merge_recursive_overrule'),
                    $arr0,
                    $arr1,
                    $notAddKeys,
                    $includeEmptyValues,
                    $enableUnsetFeature
                );
            }
        } else {
            return call_user_func(
                array('t3lib_div', 'array_merge_recursive_overrule'),
                $arr0,
                $arr1,
                $notAddKeys,
                $includeEmptyValues,
                $enableUnsetFeature
            );
        }
    }