[tz] Irish Standard Time vs Irish Summer Time

[Paul Eggert]

On 01/19/2018 10:48 AM, Michael Douglass wrote:
> Would it be more reasonable to derive a 'sanitized' tzdb from the 
> 'real' tzdb which can satisfy the requirements of extant implementations.

It should be easy to do that automatically, at least for the Irish case. 
That's something we could install into the development version after 
2018c comes out, assuming somebody writes the code.