Re: (ITS#7992) lmdb: Windows: assume file paths are UTF-8, encode to UTF-16 for WinAPI and enable compiling when UNICODE is defined

[h.b.furuseth@usit.uio.no]

Seems the test for MultiByteToWideChar() == 0xFFFD can be dropped.

The MultiByteToWideChar doc mentions U+FFFD under Return Value.
But when I test bad UTF-8 characters, it inserts 0xFFFD for the
bad character(s) in the output string.  It doesn't return 0xFFFD.
Or if we pass the MB_ERR_INVALID_CHARS flag, it returns 0 and sets
GetLastError() as usual.

(I wonder if I had a hand in this code - looks like my kind of
thing to write a draft from the Windows doc but leave the
Windows testing to someone else:-)