New API in glibmm 2.56

Member Gio::Application::property_resource_base_path_string ()
Member Gio::Application::property_resource_base_path_string () const
Member Gio::Application::set_option_context_description (const Glib::ustring& description)
Member Gio::Application::set_option_context_parameter_string (const Glib::ustring& parameter_string)
Member Gio::Application::set_option_context_summary (const Glib::ustring& summary)
Member Gio::DesktopAppInfo::get_locale_string (const Glib::ustring& key)
Member Glib::ConvertError::EMBEDDED_NUL
Member Glib::DateTime::format (const Glib::ustring& format_str) const
Member Glib::RefPtr< T_CppObject >::get () const noexcept