[avr-gcc-list] Int32 Support

[User Tomdean]

The code I posted compiles and produces correct results on other
operating systems, FreeBSD and Debian, replacing the serial port code
with putchar().  They both have 32 bit int.

The difference is in the '/10' and '%10' code, which I inserted in an
effort to find other problems.  The abs() function causes the output
to wrap at 16 bits, as in stdlib.  Replacing that with labs() produces
the correct output.  Bit by 16 bit int, again.

tomdean