* cppfiles.c (file_hash_hash):  New static function.
	(hash_string_eq):  Renamed static function to file_hash_eq.
	(_cpp_init_files):  Create file_hash table with above callbacks.
	(cpp_included):  Must use htab_find_with_hash insead of htab_find.
	(_cpp_find_find, make_cpp_dir):  Must use htab_find_slot_with_hash.

From-SVN: r74350