Another build requirement to package: libwacom

[Bastien Nocera]

Heya,

It would be great if somebody could package up libwacom:
https://sourceforge.net/projects/linuxwacom/files/libwacom/

It will be needed by the next version of gnome-settings-daemon and
gnome-control-center to provide support for Wacom tablets.

There's not much code in libwacom, and I expect the bugs against it to
be of the "sheperd data files to upstream" kind.

I'd be happy to review it if somebody packages.

Cheers