function haku_include_widget($widgets)
{
    $widgets = explode(',', $widgets);
    foreach ($widgets as $widget) {
        require get_includes_dir() . '/widget/' . $widget . '.php';
    }
}
function retro_login_logo()
{
    $login_logo = get_theme_option('wp_login_logo') ? get_theme_option('wp_login_logo') : get_includes_dir('uri') . '/images/wp_login_logo.png';
    echo '<style type="text/css"> h1 a { background: url(' . $login_logo . ') center no-repeat !important; } </style>';
}
<?php

/************************************/
/*   Standard Post Format metabox   */
$retro_format_standard = array('id' => '_retro_format_standard', 'title' => __('Media', 'haku'), 'types' => array('portfolio', 'post'), 'priority' => 'low', 'template' => get_includes_dir() . '/metabox/format_standard.php');
$retro_format_standard = new WPAlchemy_MetaBox($retro_format_standard);
/***********************/
/*   Page attributes   */
$retro_item_sidebar = array('id' => '_retro_item_sidebar', 'title' => __('Sidebar', 'haku'), 'types' => array('post', 'page'), 'priority' => 'low', 'template' => get_includes_dir() . '/metabox/item_sidebar.php');
$retro_item_sidebar = new WPAlchemy_MetaBox($retro_item_sidebar);