Passes alterable variables to specific hook_TYPE_alter() implementations.
as of Drupal 8.0. Use Drupal::moduleHandler()->alter($hook).
\Drupal\Core\Extension\ModuleHandler::alter()
function drupal_alter($type, &$data, &$context1 = NULL, &$context2 = NULL) {
return Drupal::moduleHandler()
->alter($type, $data, $context1, $context2);
}