Hello!

The Emacs Arduino mode that is currently packaged in Guix is an old,
unmaintained version, and there is a newer fork of the project by the
same name that has much more functionality. The patch attached to this
email replaces the package emacs-arduino-mode with this newer version,
which basically just amounts to changing the Git repository, hash, and
commit. There's also a substitution done that stops Emacs from
complaining about obsolete macros.

I have no idea if this is the correct way of going about this, or if I
should instead make another package with a different name to refer to
the new fork of arduino-mode. Please let me know if I should change or
revise anything.

Thanks,
-- Evan <evan.straw99@gmail.com>