Log Message:
Initial import of simulavr, contributed by Ola Eriksson in
PR pkg/27596.

The Simulavr program is a simulator for the Atmel AVR family of
microcontrollers. Simulavr can be used either standalone or as a
remote target for gdb. When used in gdbserver mode, the simulator
is used as a backend so that gdb can be used as a source level
debugger for AVR programs.