libweston: Migrate functions that operate on input objects

This include 'weston_keyboard', 'weston_touch', 'weston_pointer' and
other released classes.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
diff --git a/libweston/libinput-device.c b/libweston/libinput-device.c
index 140e87a..6941a5c 100644
--- a/libweston/libinput-device.c
+++ b/libweston/libinput-device.c
@@ -39,6 +39,7 @@
 #include <libinput.h>
 
 #include <libweston/libweston.h>
+#include "libweston-internal.h"
 #include "libinput-device.h"
 #include "shared/helpers.h"
 #include "shared/timespec-util.h"