Include <limits.h>, <stdlib.h>, <wchar.h>, <wctype.h>.

Include <limits.h>, <stdlib.h>, <wchar.h>, <wctype.h>.
(quote_name): Use mbrtowc to step through the filename string while
replacing nonprintables with question marks. Return the screen width,
not the strlen length. Do no output if the out stream is NULL.
(length_of_file_name_and_frills): Use the quote_name return value.