* lto-streamer-in.c: Include alloc-pool.h.
	(freeing_string_slot_hasher): Remove.
	(string_slot_allocator): New object allocator.
	(file_name_hash_table): Turn to hash_table<string_slot_hasher>.
	(file_name_obstack): New obstack.
	(canon_file_name): Allocate in obstack and allocator.
	(lto_reader_init): Initialize obstack and allocator.
	(lto_free_file_name_hash): New function.
	* lto-streamer.h (lto_free_file_name_hash): New.
	* lto.c (do_whole_program_analysis): Call lto_free_file_name_hash.

From-SVN: r277924