Keep an empty list of flags for now

	* lib/c-torture.exp: Keep an empty list of flags for now.
Add AVR support.

We are using environment variables to set the triple.

	* dejagnu/baseboards/avr-gdbserver.exp: New board file for running
	with a gdbserver.
	* dejagnu/baseboards/avr-sim.exp: New default board file for
	running with a simulator.
	* dejagnu/gdb-extra: New file. This fixes a issue with loading a
	program with dejagnu
	* dejagnu/gdb-stub-extra: New file. Likewise but also allow GDB
	to check the return code.
	* run-avr.sh: New file. Run BEEBS for AVR.
	* run.sh: Run BEEBS natively on x86.
	* site.exp: Add AVR to the list of targets.