Relative lflag paths in dub on Windows

[jmh530 via Digitalmars-d-learn]

Is it possible to set relative -L paths on dub for Windows? 
Absolute paths work fine, just can't get relative paths working.

I was looking at the thread here
https://forum.dlang.org/post/dkwqrwzwqbrnaamlvtld@forum.dlang.org
and came up with something like
{
     ...
     "lflags": ["-L-L..\\libs\\"],
}

where the file structure contains folders dubproject\libs and 
dubproject\source.

It didn't work though.