Not everyone is interested in every kind of deltas (and some might
even be interested knowing which files do not have overrides), so this
here is an implementation of a --type=LIST... option for
systemd-delta, that makes it possible to filter what subset of deltas
we want.
The available modifiers are masked, equivalent, redirected, overriden,
and unchanged - they should be self explanatory, and the man page
explains them in a little more detail anyway.
As a side effect, in case of overriden files, the diff output was made
optional.
By default, everything is shown (with a diff, if appropriate) except
for completely unchanged files.
Signed-off-by: Gergely Nagy <algernon@balabit.hu>