POSIX::tzset and Windows

When changing timezone in perl script. POSIX::tzset is required.

local $ENV{TZ} = 'Asia/Tokyo';
POSIX::tzset();
localtime();

But Windows does not support this.

• old Windows dies with "not implemented" error.
• newer Windows does not die. But timezone is not changed. tzset is supported only for subprocess

If you want to use tzset in tests. it's recommended to skip on windows like these.

eval {
    POSIX::tzset;
    die q!tzset is implemented on this Cygwin. But Windows can't change tz inside script! if $^O eq 'cygwin';
    die q!tzset is implemented on this Windows. But Windows can't change tz inside script! if $^O eq 'MSWin32';
};
if ( $@ ) {
    plan skip_all => $@;
}

see http://api.metacpan.org/source/KAZEBURO/Apache-LogFormat-Compiler-0.22/t/04_tz.t