Every printf()-like function sooner or later needs its vprintf()-like
buddy. The next commit will need qobject_from_jsonf_nofail()'s buddy,
and qdict_from_jsonf_nofail()'s buddy will be used later in this
series. Add both.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180806065344.7103-8-armbru@redhat.com>