Provide a way to specify the user's preferred languages
systemLanguage attribute can be used, for example, in a
<switch>, to select between elements that should only be shown depending on the user's language preferences.
Currently librsvg considers "the user's language preferences" to come from the environment; on Unix this is the
LC_MESSAGES environment variables. There's no other way to specify different language preferences.
However, the web world has moved to using BCP47 language tags. With a special syntax, these get used in the
Accept-Languages HTTP header. It would be nice if an SVG rendering service that uses librsvg could pass on the user's
Accept-Languages down to librsvg.
We need something like
rsvg_handle_set_accept_languages(handle, accept_languages_list). There are already Rust crates that can parse that HTTP header, including its weights for each specific language.