ngettext use for recursive plurals

[Miloš Komarčević]

Kudos to developers for using ngettext, but there is a slightly
complicated example in anaconda:

msgid_plural "%d of %d optional packages selected"

For Serbian (and other Slavic languages I presume), the resulting
localized version will depend on both numbers, not just the first.

I would like to file a BZ request for this to be broken up in two
parts and used recursively, as in:

msgid_plural "%d optional packages"

#. TRANSLATORS: %s is substituted by the string above
msgid_plural "%d of %s selected"

Before I do so, just wanted to check this fits ok with other
languages? Can't see a problem so far...

Regards,
Miloš