Comment 6 for bug 1850275

Following the previous discussion on the alpha mailing list [1] I suggest to introduce en_EU locale. It should be useful for the people who live in non-English speaking European countries but want to use the English user interface having their local settings for other things like metric system, paper size, etc. So far workaround solutions have been used like en_SE, en_DK, en_NL, also used in other countries. The en_EU locale would mean a generic European locale without favoring one or few countries. ISO currently marks EU country code as exceptionally reserved for European Union [2] which is kinda good but my initial idea was that EU may mean both European Union and whole Europe (including also non-EU countries). The yesexpr and noexpr entries should include the Y/N answers for as many languages as possible.

The idea is not to drop en_DK immediately although these locales can use "copy en_EU" if it makes sense.

[1] https://sourceware.org/ml/libc-alpha/2017-08/msg00308.html
[2] https://www.iso.org/obp/ui/