* pt.c (reregister_specialization): Use htab_find instead of
	htab_find_slot with INSERT.
	(maybe_process_partial_specialization, lookup_template_class_1): Change
	slot variable type to void ** to avoid aliasing problems.
	(register_specialization): Likewise.  Use slot != NULL instead of
	more expensive !optimize_specialization_lookup_p (tmpl) test.

Co-Authored-By: Diego Novillo <dnovillo@google.com>

From-SVN: r179719