configure.ac: use libinput by default

Libinput is stabilizing soon, so let's flip the default switch now. The
old input code will still be carried as an option for a while.

Cc: Peter Hutterer <peter.hutterer@who-t.net>
Cc: Jonas Ådahl <jadahl@gmail.com>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Acked-by: Jonas Ådahl <jadahl@gmail.com>

configure.ac

@@ -155,8 +155,8 @@ if test x$enable_drm_compositor = xyes; then
 fi
 
 
-AC_ARG_ENABLE(libinput-backend, [  --enable-libinput-backend],,
-	      enable_libinput_backend=no)
+AC_ARG_ENABLE(libinput-backend, [  --disable-libinput-backend],,
+	      enable_libinput_backend=yes)
 AM_CONDITIONAL([ENABLE_LIBINPUT_BACKEND], [test x$enable_libinput_backend = xyes])
 if test x$enable_libinput_backend = xyes; then
   AC_DEFINE([BUILD_LIBINPUT_BACKEND], [1], [Build the libinput input device backend])