build: nmk -- Initial import

This is initial import of NMK engine which we gonna use for
CRIU and related tools building.

It's very tiny and while here we merge it as is in future
it gonna be rather a submodule from

	https://github.com/cyrillos/nmk



An idea is to have unified build engine for most tools
we're gonna use.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>