dblog_menu_link_defaults_alter() must set 'machine_name' to avoid duplicates

Currently, hook_menu_link_defaults() has the following documentation:

/**
 * Alter links for menus.
 *
 * @param array $links
 *   The link definitions to be altered.
 *
 * @return array
 *   An array of default menu links. Each link has a key that is the machine
 *   name, which must be unique. By default, use the route name as the
 *   machine name. In cases where multiple links use the same route name, such
 *   as two links to the same page in different menus, or two links using the
 *   same route name but different route parameters, the suggested machine name
 *   patten is the route name followed by a dot and a unique suffix. For
 *   example, an additional logout link might have a machine name of
 *   user.logout.navigation, and default links provided to edit the article and
 *   page content types could use machine names node.type_edit.article and
 *   node.type_edit.page. Since the machine name may be arbitrary, you should
 *   never write code that assumes it is identical to the route name.
 *
 *   The value corresponding to each machine name key is an associative array
 *   that may contain the following key-value pairs:
 *   - title: (required) The untranslated title of the menu link.
 *   - description: The untranslated description of the link.
 *   - route_name: (optional) The route name to be used to build the path.
 *     Either a route_name or a link_path must be provided.
 *   - route_parameters: (optional) The route parameters to build the path.
 *   - link_path: (optional) If you have an external link use link_path instead
 *     of providing a route_name.
 *   - parent: (optional) The machine name of the link that is this link's menu
 *     parent.
 *   - weight: (optional) An integer that determines the relative position of
 *     items in the menu; higher-weighted items sink. Defaults to 0. Menu items
 *     with the same weight are ordered alphabetically.
 *   - menu_name: (optional) The machine name of a menu to put the link in, if
 *     not the default Tools menu.
 *   - expanded: (optional) If set to TRUE, and if a menu link is provided for
 *     this menu item (as a result of other properties), then the menu link is
 *     always expanded, equivalent to its 'always expanded' checkbox being set
 *     in the UI.
 *   - options: (optional) An array of options to be passed to l() when
 *     generating a link from this menu item.
 */
function hook_menu_link_defaults_alter(&$links) {
  // Change the weight and title of the user.logout link.
  $links['user.logout']['weight'] = -10;
  $links['user.logout']['title'] = 'Logout';
}

And dblog module adds a new item at the following code:

/**
 * Implements hook_menu_link_defaults_alter().
 */
function dblog_menu_link_defaults_alter(&$links) {
  if (\Drupal::moduleHandler()->moduleExists('search')) {
    $links['dblog.search'] = array(
      'title' => 'Top search phrases',
      'route_name' => 'dblog.search',
      'description' => 'View most popular search phrases.',
      'parent' => 'system.admin_reports',
    );
  }

  return $links;
}

Problem is, since the above array does not define $links['dblog.search']['machine_name'], the menu link is saved like the following:

*************************** 2. row ***************************
       menu_name: admin
            mlid: 62
            uuid: 03c5fb18-290e-4c50-9c04-4a14903bc478
    machine_name: NULL
            plid: 45
       link_path: admin/reports/search
        langcode: 
      link_title: Top search phrases
         options: a:1:{s:10:"attributes";a:1:{s:5:"title";s:33:"View most popular search phrases.";}}
          module: menu_ui
          hidden: 0
        external: 0
    has_children: 0
        expanded: 0
          weight: 0
           depth: 3
      customized: 0
              p1: 4
              p2: 45
              p3: 62
              p4: 0
              p5: 0
              p6: 0
              p7: 0
              p8: 0
              p9: 0
         updated: 0
      route_name: dblog.search
route_parameters: a:0:{}

Since, machine_name = NULL, the following code at menu.inc does not find the link definition while rebuilding:

function menu_link_rebuild_defaults() {
...
  if ($all_links) {
    foreach ($all_links as $machine_name => $link) {
      // For performance reasons, do a straight query now and convert to a menu
      // link entity later.
      // @todo revisit before release.
      $existing_item = db_select('menu_links')
        ->fields('menu_links')
        ->condition('machine_name', $machine_name)
        ->execute()->fetchObject();
      if ($existing_item) {
...

This causes that the menu link gets listed several times (as many as you clear caches), as you can see in the following screenshot:

Possible solutions

a) Specify at hook_menu_link_defaults() that new links must define machine_name.
b) Add logic at _menu_link_save_recursive() to make sure that 'machine_name' is set before calling drupal_save_record().