>The only difference that may come into play here is the disabling of the
>"logical path" (using the PWD environment variable) for .CURDIR, which
>currently happens only for MAKEOBJDIRPREFIX.  However, this part needs to be
>revisited.  There are reasons that make(1) should use resolved paths,
>ignoring PWD, even without MAKEOBJDIRPREFIX; the same problems can afflict
>MAKEOBJDIR and BSDSRCDIR/BSDOBJDIR.

Yep, that's why bmake's configure script has an option to disable the 
overriding of cwd with $PWD.

But if you are going to keep the $PWD handling feature you'll need to come 
up with a way to undo it or something.

This .OBJDIR: thing sounds interesting, but please keep in mind
you are frobbing some code which has many subtle twists.  
Granted those subtlies could be deemed bugs, but they are there and
have been for a long time so you can be sure that folk are relying on them.

--sjg