Replaced todo_skip stub with proper wcsxfrm() implementation.
The wide-char string transformation uses the current locale's
collation. Red Bear has no locale support, so the transformation
is the identity (same as C/POSIX locale). Cross-referenced with
Linux 7.1 time/wcsxfrm.c.
Behavior:
- n=0: count length of ws2 (excluding null terminator)
- n>0: copy ws2 to ws1 with null terminator, cap at n-1 chars
- Returns number of wide chars written (excluding null terminator)
Red Bear OS
3b28c27e00