item-list-empty.php

<?php

$items = array();

$build['list'] = array(
  '#theme' => 'item_list',
  '#items' => $items,
  '#empty' => t('You have no content, please <a href="!link">create some</a>.', array(
    '!link' => 'node/add',
  ),
);

// vs

if (count($items)) {
  $build['list'] = array(
    '#theme' => 'item_list',
    '#items' => $items,
  );
}
else {
  $build['list'] = array(
    '#theme' => 'container',
    0 => array(
      '#markup' => t('You have no content, please <a href="!link">create some</a>.', array(
        '!link' => 'node/add',
      ),
    ),
  );
}