Convert serapi_get_engine_list() into hook

Patch in attachment.

No. None of the function can contain 'hook' word.
When you execute module_invoke_all() it will automatically call all the instances of this hook and merge the data. No need to define hook in some special way.
See: http://api.drupal.org/api/function/module_invoke_all/6 ($function = $module .'_'. $hook;)
In my opinion hook_search_engine_list is a better name than get_engine_list, because in hooks you set those engines, not get.
Serapi module it-self contains implementation of this hook, and I've got following function defined in my separated module:

/**
 * Implementation of hook_search_engine_list
 *
 * @return Array
 * Array of search engines
 */
function mymodule_search_engine_list() {
  return array(
    'doc-live' => array(
      'host_pattern' => 'xxx.co.uk',
      'query_param' => 's'
    ),
    'doc' => array(
      'host_pattern' => 'doc',
      'query_param' => 's'
    ),
  );
}

where I've defined my local environment, production and live server.
Functionality is tested and works on my environment.
I need those internal search engines to generate proper breadcrumbs and have access to search keywords from internal search engine.
Some examples of usage serapi module in crumbs module
#926266: How to change the path of the crumbs?
#933230: Add debug option to show which method has been called
#925382: Method of override breadcrumb completely

Thanks.
It will be great.