libzip and non-ascii home directories on Windows

[Dirk Hohndel]

So this problem apparently still isn't fixed. How frustrating.
The current 4.4.1 Windows binaries are build with libzip version
42199fe38a16 which should contain all the necessary fixes, yet exporting
to divelogs.de still fails without any error.

I have now created a new Windows VM where I was able to create a local
user with the useful user name of Møtörhæđ Łüñçïß - and I can reproduce
the problem. I built the latest master of libzip and dropped it into the
program folder - still the same problem.

Before I try to sprinkle the sources with tons of debug output... Lubomir,
any idea what's up here?

Thanks

/D