[patches] make xdm better for multiple monitors

[Warren Block]

xdm doesn't handle multiple monitors or large virtual screens well,
so I've worked up a couple of patches that add capabilities:

1. start with the mouse pointer in the login window
2. open the login window on a specific monitor

The two can be used individually or combined.  Patches and more detail 
in the readme.txt here:

http://www.wonkity.com/~wblock/xdm-patches/

Feedback appreciated.

-Warren Block * Rapid City, South Dakota USA