Plurals in Welsh

According to Plural Mediawiki disagrees with Gettext and CLDR rules about the plural forms. Which one is right and which one needs to be fixed?

You should find that the PLURAL rules in CLDR have been amended since your data was gathered in September 2010. CLDR and Wikimedia should now have the same rules.

That leaves Gettext. Do you know the Gettext equivalent for Welsh?

Sadly, I know nothing about Gettext.

cy      nplurals=4; plural=(n == 1) ? 0 : ( (n == 2) ? 1 : ( (n != 8 && n != 11) ? 2 : 3 ) );

Am I right in thinking that there is a rule for 0;1;8&11;everything else?

I believe that there is a very obscure exception for mutation with 8 and 11, which is used with three words only, two of which (sterling pound and hundred) will not appear as words anyway, and is very old-fashioned. The rule for 8 and 11 used to be in CLDR as well, but the Bedwyr Language Centre, at my request, negotiated with CLDR to replace it with the most important rules, for 0;1;2;3;6;everything else.

Apparently, the CLDR has:

 Rule P:
   zero: n is 0
   one: n is 1
   two: n is 2
   few: n is 3
   many: n is 6

I'll try to update the Gettext rule to match