wcsnlen
=======

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/wcsnlen.html

Gnulib module: wcsnlen

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: Mac OS X 10.5, FreeBSD 6.0, NetBSD 7.1, OpenBSD 6.7, Minix 3.1.8, HP-UX 11, IRIX 6.5, Solaris 10, Cygwin 1.5.x, mingw.

Portability problems not fixed by Gnulib:

  * On Windows and 32-bit AIX platforms, wchar_t is a 16-bit type and therefore cannot accommodate all Unicode characters.