BUG #16103: Initdb does not respect country for language

The following bug has been logged on the website:

Bug reference: 16103
Logged by: Simon Wimmesberger
Email address: simon(dot)wimmesberger(at)zoetis(dot)com
PostgreSQL version: 10.10
Operating system: Windows Server 2008 R2
Description:

When using the enterprisedb installer on Windows and I select the language
"German, Austria" it is passed to initdb with "German,Austria". When I look
at the database property of the initialized database the "collation" and
"character type" is set to "German_Germany.1252" instead of the expected
value of "German_Austria.1252". When I call initdb directly with
"German_Austria.1252" it works as expected. In our usecase we really want to
use the enterprisedb installer therefore selecting the language should work
as expected.

I have also tried to select "Englisch, Ireland" in the installer it is again
passed to initdb as "English,Ireland" but the database is then wrongly
initialized with "English_United States.1252" - so it seems like that the
installer somehow passes the Language/Country wrong the initdb executable or
initdb does not respect the country when passed in this format.