Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
nailing-cargo again should clean up such a mess. Unfortunately it is
not possible to fix this bug because the cargo team have deliberately
made cargo inflexible -
- [issue#6715](https://github.com/rust-lang/cargo/issues/6715).)
+ [issue#6715](https://github.com/rust-lang/cargo/issues/6715).
* Out of tree builds require a unified filesystem view: eg, different
users on the same host, NFS, or something. This could be improved.