[Xfce-i18n] Help with plurals in po files

[Geraint Rowlands]

I'm translating Xfce4.4 to Welsh, and am currently working on
thunar.po. I've tripped up on the plurals for file copies (%uth copy
of %s).

Welsh plurals generally work the same as English (book-books =
llyfr-llyfrau for single or plural). Numerics are a lot more
complicated though.

1: -af
2: -il
3,4: -ydd
5-10: -ed
11: -eg
12: -ed
13,14: -eg
15: -ed
16, 17: -eg
18: -ed
19: -eg
20-39: ain
and that's surely far enough.

My current solution is to say 'copy %u of %s' instead, but how would I
accomodate these forms in a .po file if I were unable to worm my way
out of it?

Thanks in advance.