make: prepare crtools build for submake calls

The reason for this patch is that only phony goal can depend on phony targets.
But with protobuf we will have to execute phony targets prior to main target
build.
So, this patch set add few new goals and dependences:

1) "all" become default goal.
2) new goals "deps" and "preq" introduced.
3) "all" depends on "deps" and "crtools".
4) All global goals like "zdtm" and "test-legacy" now depends on "all".

Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>