GNAT JVM/AVR/Mindstorms on GNU/Linux?

[deadlyhead <deadlyhead@gmail.com>]

Just wondering if anybody has had any success using GNAT targeting
either JVM, AVR-elf or Mindstorms NXT from a GNU/Linux environment.
I've been trying to build a JVM cross-compiler on my Debian system
with the latest stable GCC release, but have met only with failure.
Comparing the patches provided by Adacore and the GCC development
tree, it looks like I might have success when GCC 4.6 is released, but
until then I think I'm stuck.

I'd really like to develop for the NXT system, too.  I have some
friends whose kids who would be pretty excited at having robots that
could be controlled from their computers, and at least a couple of
them are old enough to be introduced to some basic programming,
robotics and computer science geekery.  I've been introducing them all
to the joys of free software (using GNU/Linux and the Gimp,
SuperTuxKart, etc), and it seems a shame that I can't use the same
system to teach them about Ada and robotics at the same time.

I'm just fishing for ideas here, and would like to know if anybody has
tried/had any success with targeting embedded systems with GNAT from
GNU/Linux (I include the JVM here because I'm looking at the
possibility for developing Android apps in Ada, too).  Am I crazy to
think that a GCC-based compiler should work no GNU systems first, then
other systems later?