Add cmp -n and create wrappes for diffutils and grep

Add a patch to include support for option -n in cmp to compare at mostn bytes.

Also, since some scripts relay on long options which are not supported by busybox create a simple wrapper to convert long options into short ones.

https://phabricator.apertis.org/T8146

Signed-off-by: Walter Lozano walter.lozano@collabora.com