The tow* functions use an included case conversion table which can be
generated from Unicode data.
The isw* functions use a character categories table (provided by
categories.c) which can be generated from Unicode data.
Delegation between current-locale and specific-locale-dependent functions
was reverted towards the generic locale-dependent functions (*_l.c);
this is however only relevant on systems with non-Unicode wide character
locales, thus not on Cygwin.
Thomas Wolff