The ipc_unixsocket.h and process.h internal headers don't need to include event_notifier.h, the former because a forward declaration suffices, and the latter because it doesn't use event notifiers. Remove the unnecessary include, and include signal.h instead which is required and was included indirectly through event_notifier.h. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>