Can not compile for single-byte charsets

QFileDialogPrivate::maxNameLength(const QString &path) (in \src\gui\dialogs\qfiledialog_p.h) does not compile if a single-byte charset is used.
Line ~149:

if (::GetVolumeInformation(reinterpret_cast<const wchar_t *>(drive.utf16()), NULL, 0, NULL, &maxLength, NULL, NULL, 0) == FALSE)

I'd propose something like:

#if defined(_UNICODE) || defined(_MBCS)
if (::GetVolumeInformation(reinterpret_cast<const wchar_t *>(drive.utf16()), NULL, 0, NULL, &maxLength, NULL, NULL, 0) == FALSE)
#else
if (::GetVolumeInformation(drive.toLocal8Bit().constData(), NULL, 0, NULL, &maxLength, NULL, NULL, 0) == FALSE)
#endif

as a patch.