Declaration of hs_taxonomy_views_handler_filter_term_node_tid should be compatible with that of...

See #1170192: Port Hierarchical Select Taxonomy Views (for exposed filters in Views) to Drupal 7.

It's an issue with NOT using a reference sign before $options argument.
I changed it, and the error message is gone.

In views_handler_filter_term_node_tid.inc, line 13
this is the header:

class views_handler_filter_term_node_tid extends views_handler_filter_many_to_one {
  // .........
   function init(&$view, &$options) {
      // ..........
   }
   // ............
}

in hs_taxonomy_views_handler_filter_term_node_tid.inc, line 9

class hs_taxonomy_views_handler_filter_term_node_tid extends views_handler_filter_term_node_tid {
   // ............
  function init(&$view, $options) {
     // ............
  }
   // ............
}

So there's no reference sign before $options.

==============================================================

By the way, I got a little bit different error (not referring to require_once()):

Strict warning: Declaration of hs_taxonomy_views_handler_filter_term_node_tid::init() should be compatible with that of views_handler_filter_term_node_tid::init() in _registry_check_code() (line 3062 of ...../includes/bootstrap.inc).

Yes, this works. I added the reference sign before $options in hs_taxonomy_views_handler_filter_term_node_tid.inc, line 9 and the warning disappeared.

Views integration is not yet supported. See #1170192: Port Hierarchical Select Taxonomy Views (for exposed filters in Views) to Drupal 7.