In case multiple builds share UNINATIVE_DLDIR's location, one build
might be in the process of downloading the tarball while another is
just checking whether the tarball exists. Check for the done file
instead and rely on the fetchers lockfile mechanism in case two
builds are running.
Signed-off-by: Stefan Agner <stefan.agner@toradex.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
