Function glib_sys::g_key_file_get_locale_for_key

pub unsafe extern "C" fn g_key_file_get_locale_for_key(
    key_file: *mut GKeyFile, 
    group_name: *const c_char, 
    key: *const c_char, 
    locale: *const c_char
) -> *mut c_char

This is supported on crate feature v2_56 only.