Actually, I took the Linux compat code one step further in the 
alternate root handling (perhaps too far due to a misunderstanding
with Christos):

- relative pathnames are untouched.
- opening a file for reading (in various forms) checks if the file
  exists under /emul/linux
- creating a file (including symlink() and rename()) checks if the directory
  that it should be created in exists in /emul/linux and then attempts
  to create it there.

The last point is not done in the svr4 emul code, only in the Linux code
currently.

Before we make /emul directories the default, we should agree on the semantics.
What are the objections to what I did? It seemed better to me, because
it made things like the Linux version of ldconfig work correctly. Any
examples of where this would break?

Also, a good directory for common compat code seems /sys/compat/common

- Frank