gnu: Prefer libgudev as GUDEV (GObject bindings for libudev) provider.

* gnu/packages/gnome.scm (upower, gnome-settings-daemon, rhythmbox)
  gnu/packages/xfce.scm (thunar, thunar-volman): Switch to libgudev as
  GUDEV provider.

gnu/packages/gnome.scm

@@ -2315,8 +2315,8 @@ faster results and to avoid unnecessary server load.")
        ("intltool" ,intltool)
        ("python" ,python)))
     (inputs
-     `(("eudev" ,eudev)
-       ("dbus-glib" ,dbus-glib)
+     `(("dbus-glib" ,dbus-glib)
+       ("libgudev" ,libgudev)
        ("libusb" ,libusb)))
     (home-page "http://upower.freedesktop.org/")
     (synopsis "System daemon for managing power devices")
@@ -2401,7 +2401,7 @@ services for numerous locations.")
        ("docbook-xsl" ,docbook-xsl)))
     (inputs
      `(("colord" ,colord)
-       ("eudev" ,eudev)
+       ("libgudev" ,libgudev)
        ("upower" ,upower)
        ("polkit" ,polkit)
        ("pulseaudio" ,pulseaudio)
@@ -3001,8 +3001,8 @@ which can read a large number of file formats.")
       ("gstreamer" ,gstreamer)
       ("gst-plugins-base" ,gst-plugins-base)
       ("gst-plugins-good" ,gst-plugins-good)
-      ("eudev" ,eudev)
       ("totem-pl-parser" ,totem-pl-parser)
+      ("libgudev" ,libgudev)
       ;;("libmtp" ,libmtp) FIXME: Not detected
       ("libsecret" ,libsecret)
       ("libsoup" ,libsoup)

gnu/packages/xfce.scm

@@ -457,8 +457,8 @@ like appearance, display, keyboard and mouse settings.")
        ("intltool" ,intltool)))
     (inputs
      `(("exo" ,exo)
-       ("gudev", eudev)
        ("libexif" ,libexif)
+       ("libgudev" ,libgudev)
        ("libnotify" ,libnotify)
        ("libxfce4ui" ,libxfce4ui)
        ("pcre" ,pcre)
@@ -488,7 +488,7 @@ fast.")
        ("intltool" ,intltool)))
     (inputs
      `(("exo" ,exo)
-       ("gudev" ,eudev)
+       ("libgudev" ,libgudev)
        ("libnotify" ,libnotify)
        ("libxfce4ui" ,libxfce4ui)))
     (home-page "http://www.xfce.org/")