* source.c (symtab_to_fullname): Test 'r >= 0'.

	* source.c (symtab_to_fullname): Test 'r >= 0'.
	(psymtab_to_fullname): Likewise.
	(get_filename_and_charpos): Make a cleanup.
	(forward_search_command): Likewise.
	(reverse_search_command): Likewise.
	* exec.c (exec_file_attach): Close scratch_chan on failure.
	* nto-procfs.c (procfs_open): Make a cleanup.
	(procfs_pidlist): Likewise.
	(do_closedir_cleanup): New function.