bug#59479: expand fails on non-ASCII characters

[Thomas Wolff]

echo -e "o\tx\nö\tx" | expand
fails to align

I know this is a duplicate of 
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=6934, 
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=13957 (my own) and 
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=28038 but I'm reporting 
again because
1. those issues have been marked "Severity: wishlist" which is not 
appropriate - guys, we have 2022 and Unicode support is essential!
2. https://lists.gnu.org/archive/html/coreutils/2020-11/msg00024.html 
claims the issue would have been fixed in 8.32 but it wasn't and it 
isn't in 9.0.