Drupal views: force contextual filter to use logical OR condition

drupal.views.filter.or.php

/**
 * @file: MY_MODULE.views.inc
 *
 * Implementation of hook_views_query_alter().
 * @param view $view
 * @param views_plugin_query_default $query 
 */
function MY_MODULE_views_query_alter(&$view, &$query) {
  if ($view->name == 'MY_VIEW') {
    $query->where[0]['type'] = 'OR';
  }
}

/**
 * @file: MY_MODULE.module
 *
 * Implemented hook_views_api().
 */
function MY_MODULE_views_api() {
  return array(
    'api' => 3,
  );
}