wcsncmp
¶POSIX specification:
https://pubs.opengroup.org/onlinepubs/9799919799/functions/wcsncmp.html
Portability problems fixed by Gnulib:
wchar_t
is signed, on some platforms:
glibc 2.14.1 on x86 or x86_64, musl libc 1.2.3, macOS 14,
FreeBSD 13.2,
NetBSD 10.0, OpenBSD 7.2, Solaris 11.4.
Portability problems not fixed by Gnulib:
wchar_t
is a 16-bit type and therefore cannot
accommodate all Unicode characters.