Bug#472180: dbus interacts badly with Xprt

[Drew Parsons <dparsons@debian.org>]

dbus is causing Xprt to using 95% cpu.  When ./configured with
--disable-dbus, Xprt behaves normally.  

Tested back to around 17d85387d1e6851d35474b65929e268ca64ef65b (5 Feb
2007 / 18 Jan 2007)    [to build, need to add (cherry-pick)
fb8eb230356c70ea3b417ea6598dfb126ad50db7 for InputDevice stubs and
25499ad777f50e6bf8230347eee9e87a1166246f for DDXRingBell().  Add "-lhal
-ldbus-1" by hand to Xprt_LDADD in obj-i486-linux-gnu/hw/xprint/Makefile
to link in dbus.]

Going back further (without disabling dbus) is difficult, because Xprt
builds but gives the runtime error:
[dbus] couldn't take over org.x.config: (null) ((null))

I think this means the bug has come out of the input-hotplug
development, which entered xserver 1.4.