Stop using static variables and clean up when we're done. [Emilio: update to latest weston_layer API] Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk> Signed-off-by: Emilio Pozuelo Monfort <emilio.pozuelo@collabora.co.uk> Reviewed-by: Micah Fedke <micah.fedke@collabora.co.uk> Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net> [Pekka: fix build after previous commit's fix]