AVR simulator support

I'm running the GCC testsuite on AVR using the simulator included in
binutils-gdb, and an avr-sim.exp file, which essentially duplicates
all the other *-sim.exp files.

Is that the right way, or should I be using generic-sim.exp or multi-sim.exp?

If the right way is to use an avr-sim.exp file, what's the best way of
adding one to the DejaGNU distribution? I think the changes qualify as
"tiny", but obviously signing a copyright assignment is not a problem
if that's the preferred way.

The only complications are that the AVR simulator needs an extra
object file to be linked, an extra -mmcu=* flag to be provided during
compilation, and that a different libc is used.

I'm attaching my avr-sim.exp for reference.

Pip Cet