Calendar support in localization

Hi all,
My country(Ethiopia) is one of the nations that uses different kind of
calendar than what PostgreSQL have so we are deprived from the benefit of
data datatype. We just uses String to store date that limits our
application quality greatly. The lag became even worst once application and
system time support is available and it seems to me it is not fair to
suggest to add other date data type kind and implementation for just
different calendar that even not minor user group. Having calendar support
to localization will be very very very very exciting feature for none
Gregorian calendar user group and make so loved. As far as i can see the
difficult thing is understanding different calendar. I can prepare a patch
for Ethiopian calendar once we have consensus.

I cc Thomas Munro and Vik because they have interest on this area

Please don't suggests to fork from PostgreSQL just for this feature

regards
Surafel