[hurd - ACPICA]: glue code for libacpica

[Damien Zammit]

ACPICA is the upstream ACPI implementation.
The upstream code is hosted on https://github.com/acpica/acpica

It has filtering that reprocesses the upstream reference
implementation into something they call "linuxized" (more readable
code). I have implemented the following glue to snarf this
linuxized version into hurd.

You can generate the code by checking out a copy of the upstream code,
running: ./generate/linux/gen-repo.sh
then copying the resulting files into place within the hurd tree under
libacpica/

I changed the way the tree is laid out slightly because I didn't like
the layout of include/ being completely separate from the driver/ tree.
I put:

include/acpi -> libacpica/acpi
drivers/acpi/acpica -> libacpica

This simplifies the tree a bit for building it as a hurd library.

Please review, it currently compiles with zero warnings, but does not
run.  I also suggest writing a simple test program that just calls:

acpi_init();

Damien