nailing should not be recommended

When I invented nailing-cargo I thought of the privsep stuff as an afterthought. But now it is a primary objective (for me and at least two other people). The documentation reflects the previous understanding.

In fact, unless you actually want to override dependencies from crates.io, you should not put anything in subdirs. Doing that has all manner of side effects you don't want if you don't need them. See eg dgit-team/tag2upload-service-manager#19 (closed)

The documentation is misleading and nailing-cargo even prints a warning if you have an empty subdirs.

My usual practice is to do something like this:

   xsubdirs='''
   derive-deftly
   tag2upload-service-manager
   '''

And then I can delete the x if I need to do some exciting things.

See also #4 (closed) which I think is probably dealt with by (i) --no-nail (ii) the ability to have subdirs empty, supposing we fix the docs/warning.