left by an interrupted run.
* Out of tree builds require a unified filesystem view: eg, different
- users on the same host, NFS, or something. This could be improved.
+ users on the same host, NFS, or something.
+
+ Specifically, the invocation and build execution environments must
+ both have visibility of the source and build directories, at the
+ same absolute pathnames. The invocation environment must be able
+ to write to the build environment (but vice versa is not
+ required).
+
+ This could be improved.
* The alternative `Cargo.lock` filename must currently be a leafname. I
think fixing this just involves review to check other values work