bug#36887: coreutils-8.31: printf chokes on \u0041

[Ulrich Mueller]

[Forwarding bug https://bugs.gentoo.org/680244 as requested by the
Gentoo package maintainer.]

According to printf(1):

   Interpreted sequences are:
   [...]
   
   \uHHHH Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)

   \UHHHHHHHH
          Unicode character with hex value HHHHHHHH (8 digits)

It does not work, though:

$ /usr/bin/printf '\u0041\n'
/usr/bin/printf: invalid universal character name \u0041
$ /usr/bin/printf '\U00000041\n'
/usr/bin/printf: invalid universal character name \U00000041

Other tools interpret the sequence correctly:

$ printf '\u0041\n'   # bash
A
$ echo -e '\u0041'    # bash
A
$ zsh -c "echo -e '\u0041'"
A
$ emacs -Q --batch --eval '(princ "\u0041\n")'
A
$ python -c "print ('\u0041')"
A
$ ruby -e 'print("\u0041\n")'
A