Marks a word as "dirty" (changed), or retrieves the list of dirty words.
This is used during indexing (cron). Words that are dirty have outdated total counts in the search_total table, and need to be recounted.
function search_dirty($word = NULL) {
$dirty =& drupal_static(__FUNCTION__, array());
if ($word !== NULL) {
$dirty[$word] = TRUE;
}
else {
return $dirty;
}
}