[RFC libinput 0/2] Buttonset interface

[Peter Hutterer]

First a heads-up: these patches are an RFC and not fully polished yet. At
this point I've looked at everything long enough that I won't see any bugs
anymore though. And now we're at the point that we need some feedback
anyway.

This set adds a buttonset interface. The tablet branch so far only supports
tools (stylus, eraser, etc.) but it doesn't actually handle the
buttons/wheels/strips on the tablet itself (the "pad").
Rather than introducing a custom interface for the pad or (ab)using the
tablet interface we added a "buttonset" interface - a generic interface for
any device with buttons and random axes that isn't supposed to control the
cursor.

The interface is generic, the backend (patch 2/2) is very wacom specific
because of the various quirks the protocol uses. Once we have other devices
that want to use this we can start factoring this out a bit, for now it's
all piled together.

Comments appreciated.

Cheers,
  Peter