Here we introduce actions:

 - "piegen" to generate blobs, which is used
    by criu already;

 - "cflags" and "ldflags" to print out options
   needed for compiler and linker when building
   compel compatible objects.

We rather moved old "main" function body into
piegen helper function and implement the rest
of actions since they are one-liners.

Note the usage uses new "compel" brand, but it's
safe because we don't export anything yet.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>