[PATCH libinput 0/4] Wheel tilt scroll source

[Peter Hutterer]

Quite a few mice have tilt-capable wheels for horizontal scrolling. We can't
detect those automatically so we'll have to rely on systemd/udev for the
tagging. But despite that, we should be honest about the scroll source and
mark them as tilt where possible rather than pretending that they're degrees
like the wheel promises to be.

For backwards compat, I'm leaving the actually returned value as-is, so most
callers that don't support the new scroll source should just work fine.
There's no real value to return anyway despite "tilted" and returning just
-1 or 1 here would likely break the world. And I like this world, I don't
have another one available.

Cheers,
  Peter