Returns an array of links to be rendered as the Main menu.
function menu_main_menu() {
$config = config('menu.settings');
$menu_enabled = module_exists('menu');
// When menu module is not enabled, we need a hardcoded default value.
$main_links_source = $menu_enabled ? $config
->get('main_links') : 'main';
return menu_navigation_links($main_links_source);
}