I need those function for backport of CharsetConverter from Kodi. Source code of that file is [here](https://github.com/xbmc/xbmc/blob/master/xbmc/platform/win32/CharsetConverter.cpp). I also need `vswprintf` for wchar variant of StringUtils::Format(...). Look [here](https://github.com/xbmc/xbmc/blob/Nexus/xbmc/utils/StringUtils.cpp#L300) - [ ] WideCharToMultiByte - [ ] MultiByteToWideChar - [ ] vswprintf
