dbus: Don't search for Xlibs if useX11 is false.

This particularily fails when using non-chrooted builds.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/development/libraries/dbus/default.nix

@@ -57,7 +57,7 @@ let
       "--sysconfdir=/etc"
       "--with-session-socket-dir=/tmp"
       "--with-systemdsystemunitdir=$(out)/etc/systemd/system"
-    ];
+    ] ++ lib.optional (!useX11) "--without-x";
 
     enableParallelBuilding = true;