[Bug-tar] Relative or no path at all in a tar archive?

[Angel Tsankov]

How can I add a couple of files to a tar archie with a relative path, e.g.:
c:\dir\file1 |                 | dir\file1
c:\dir\file2 |-> archive.tar = | dir\file2
c:\dir\file3 |                 | dir\file3