gnu: glib: Add "bin" output.

gnu: glib: Add "bin" output.

Fixes <http://bugs.gnu.org/17853>.

* gnu/packages/glib.scm (glib)[outputs]: Add "bin".
  (gobject-introspection)[native-inputs]: New field.
* gnu/packages/avahi.scm (avahi)[native-inputs]: Add glib:bin.
* gnu/packages/gnome.scm (brasero, libgnome-keyring, evince,
  gsettings-desktop-schemas, libnotify, gtkglext): Likewise.
* gnu/packages/gstreamer.scm (gstreamer, gst-plugins-base,
  gst-plugins-base-0.10): Likewise.
* gnu/packages/gtk.scm (atk, pango, gdk-pixbuf, gtk+-2, gtk+):
  Likewise.
* gnu/packages/linux.scm (udev): Likewise.
* gnu/packages/pdf.scm (poppler): Likewise.