[AD] About Javier Gonzalez's patch

["Eric Botcazou" <ebotcazou@xxxxxxxxxx>]

Javier Gonzalez recently posted a patch which aims at solving the
Windows-only 'mouse doesn't move fast enough in hires modes' bug.
I haven't tested it yet but it seems to actually fix the problem; it does
that by reproducing the behaviour of the Windows built-in mouse driver:
using two threshold values to scale up the mickeys by 2 or 4. So the
consistency with the host OS is enforced.

What I wonder is whether we shouldn't also take care of the consistency with
the others ports of Allegro. The DirectDraw mouse interface is very basic:
only raw hardware mickeys are returned without taking any speed or
resolution factor into account, so we have to do the entire job.
Now on others platforms (DOS and X11 at least, BeOS ?), a significant part
of this job is performed by the system mouse driver: how are this drivers
dealing with the screen resolution ? Are they using threshold values too or
a global scaling factor based on the resolution ?