[DRE-maint] Bug#874365: ruby-gdk3: Typelib file for namespace 'Gdk' (any version) not found (GLib::Error)

[JD Friedrikson]

Package: ruby-gdk3
Version: 3.1.0-1
Severity: grave
Justification: renders package unusable

Hello there,

I was attempting to make a small thing with gtk3 (via ruby) this morning
and ran into an error with one of its dependencies:

```
/usr/lib/ruby/vendor_ruby/gobject-introspection/loader.rb:37:in `require': Typelib file for namespace 'Gdk' (any version) not found (GLib::Error)
	from /usr/lib/ruby/vendor_ruby/gobject-introspection/loader.rb:37:in `load'
	from /usr/lib/ruby/vendor_ruby/gdk3.rb:56:in `init'
	from /usr/lib/ruby/vendor_ruby/gtk3.rb:64:in `init'
	from /usr/lib/ruby/vendor_ruby/gtk3.rb:40:in `const_missing'
	from ./pomodoro:5:in `<main>'
```

It seems to fail with some pretty basic usage:

```
#!/usr/bin/env ruby

require 'gtk3'

window = Gtk::Window.new('test')
window.show
Gtk.init
Gtk.main
```

As the error refers missing files, I figure this would be a bug related
to the package. Please let me know if I'm mistaken.

Cheers,
JD

-- System Information:
Debian Release: 9.1
  APT prefers stable
  APT policy: (600, 'stable'), (500, 'stable'), (300, 'testing'), (1, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.9.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8), LANGUAGE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages ruby-gdk3 depends on:
ii  ruby                        1:2.3.3
ii  ruby-atk                    3.1.0-1
ii  ruby-cairo-gobject          3.1.0-1
ii  ruby-gdk-pixbuf2            3.1.0-1
ii  ruby-gobject-introspection  3.1.0-1
ii  ruby-pango                  3.1.0-1

ruby-gdk3 recommends no packages.

ruby-gdk3 suggests no packages.

-- no debconf information