diff utils: Update from version 3.2 to 3.3

diff utils: Update from version 3.2 to 3.3

** New features
--new-file (-N) and --unidirectional-new-file now allow comparisons to
"-".  A standard input that's closed acts like a nonexistent file.

A file name containing spaces, double quotes, backslashes or control
characters is now encoded in a diff header as a double-quoted C string
literal.  The escape sequences \\, \", \a, \b, \f, \n, \r, \t, \v and
\ooo (a three-digit octal number between 0 and 255) are used.