* lto-plugin.c: (non_claimed_files): New static var.
	(linker_ouput_known): New static var.
	(all_symbols_read_handler): When user specifies linker output do not
	imply it; output warning when nonlto-rel mode is forced.
	(claim_file_header): Record number of nonclaimed files.
	(process_option): Remember if linker output is known

From-SVN: r260960