[cvsnt] Drive-root (e.g., ":local:P:\") CVSROOT support.

[Brian Cowan]

I have a customer using a (I think twice-mapped) drive as his CVS root. 
He's doing this:
set CVSROOT=:local:P:\
Subst P: Y:\Dir1\Dir2

When he runs a tool of ours that hard-codes the cvs get, he gets the 
following error:
cvs [checkout aborted]: Local access to network share not supported (Use 
-N to override this error).

So, the questions are:
1) Did tricks like the above ever work?
2) When did it stop working?
3) Will setting CVSROOT=:local:Y:\Dir1\Dir2 work?
4) If the answer to #3 is "no", what version did it stop working (as 
I've done #3 in the not-too-distant past)?

I seem to recall CVS not liking CVSROOT environment variables pointing 
to the root of the drive, wanting to be at least one level down.