coding_arg_coding_type 10950 src/coding.c     Lisp_Object coding_type = args[coding_arg_coding_type];
coding_arg_coding_type 12184 src/coding.c         args[coding_arg_coding_type] = Qraw_text,
coding_arg_coding_type 12206 src/coding.c     plist[5] = args[coding_arg_coding_type] = Qundecided;