Undid previous commit: back to --archive.

Concerning the hassle with cygwin, NTFS backup medium, and permissions
it turned out that adding an fstab entry for the backup medium with
the noacl flag does the trick. Example:

E:/rsbk /rsbk NTFS binary,noacl,user 0 0

I had a bad feeling anyway doing that modification only for
a special system landscape.