`make test COMPAT_TEST=y` will build all executable tests as i386 ELFs.

For building tests, need the following libraries from multilib:
libaio.i686 libaio-devel.i686 libcap-devel.i686 libcap.i686

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>