Support Hijri calendar

[Suhail Alkowaileet]

I would like to support the lunar Hijri calendar(see: 
https://en.wikipedia.org/wiki/Hijri ) to the jdk and I'm just asking 
should I do something before doing this?
My plan is to clone the jdk8/l10n/jdk and add the appropriate files to 
of the Hijri and push them back. I'm going to use the Umm al-Qura 
calendar as the way of calculating(see: 
https://en.wikipedia.org/wiki/Hijri#Saudi_Arabia.27s_Umm_al-Qura_calendar ).