iswupper
========

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

Gnulib module: wctype-h

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8.

  * This function cannot be called from plain inline or extern inline functions on some platforms: OS X 10.8.

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. However, the Gnulib function c32isupper, provided by Gnulib module c32isupper, operates on 32-bit wide characters and therefore does not have this limitation.