The conversion to the OPTION macros in c3f4c1b8d6 ("journalctl:
convert to OPTION macros") replaced strv_copy_unless_empty() with
strv_copy().
This is problematic because the positional arguments are now an empty
strv rather than NULL when none are given, but `--{list,dump}-catalog`
rely on that.
Instead let's hand NULL back to them when there is nothing on the
command line.
Chris Down
2ff84cf0a1