[Koha] Opac default language

[Stefano Bargioni]

Some years ago I proposed a (raw) solution to set the opac default language other than English: see
http://koha.1045719.n5.nabble.com/Set-principal-language-td4263943.html
If I'm not wrong, this solution was broken by the HttpOnly flag set to true for cookie KohaOpacLanguage at C4/Templates.pm line 310.
Is there a way to solve this? Do we need an enhancement, like a new syspref?
Thanks. Stefano