* lto.c (get_filename_for_set): Look for cgraph node and if none found, use
	default name.
	(lto_wpa_write_files): Write any non-empty partition.

	* cgraph.h (cgraph_node_set_nonempty_p, varpool_node_set_nonempty_p): New.
	* lto-cgraph.c (input_cgraph): Remove call to lto_mark_file_for_ltrans.
	* lto-streamer.h (lto_file_decl_data): Remove needs_ltrans_p.
	(lto_file_needs_ltrans_p, lto_mark_file_for_ltrans,
	cgraph_node_set_needs_ltrans_p): Remove.

From-SVN: r158943