Nissan Patrol 4x4 (Africa)

What would cause this?

The boot pipe connecting to the compressor housing sometimes "sweat" a bit of oil. Not sure if this is the case as it looks reasonably dry there on the photo.
It's not uncommon actually and I have seen it on many cars. because of the breather system, there will always bee oil in the boost system so any small leak will have oil coming out.
So in short, I don't think your turbo is broken.

Its my friends car and I think the run off looks more than normal. He says he hays oil on his garage floor all the time. I owned a DI before and did not have this issue.