Also link wayland-client, as we use bits from it.

Fixes linking on some toolchains where linkage is a bit more restrictive.

Change-Id: I7ec3f2bde009ce6d2e20e4b500a96d234cdcc301
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
inputdevice: Null check m_data_device

Change-Id: Ibe4184c692775ebac89098e5d332f72280184b58
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>