clean operation follows soft links

Hi

I noticed that if an artifact folder contains a soft link to an external directory then a clean-before-build operation will delete the external directory rather than just the link to it.

I'm not sure this is a fault as such, but it should probably be mentioned in the documentation.
It may cause a problem for someone if, for example, a build step that makes the link as part of its processing then exits for some reason before removing the link.