How to initialize gtkmm without Gtk::Application?

[Rodolfo Ribeiro Gomes <rodolforg gmail com>]

Hello.

I'm creating a plugin for glade in order to be able to create interfaces using custom C++ widgets and edit its properties via glade.

Everything is (finally) working here. My problem now is how to properly initialize gtkmm without using the deprecated Gtk::Main::init_gtkmm_internals().

As it's a plugin, I have no reason to create an Gtk::Application-derived class/object…