[PATCH] Make -nocursor a runtime option to and remove the compile time NULL_ROOT_CURSOR

[John Tapsell]

> Hmm, that seems a little odd.  Seems like there are three camps here:
>    * People writing display drivers (let's call them 'the minority')
>      want a stipple and cursor.  -> -retro
>    * People starting regular desktop environments want the default
>      behaviour.  (Though I have slight doubts.  I'd fall back on the
>      default cursor being a NULL cursor unless forced otherwise, and
>      IIRC the behaviour here is to suppress cursor realisation, which
>      means you come back to an ugly root cursor, but that's fixable.)
>    * People running consumer/embedded systems who can't trust their
>      apps not to try to change the cursors want to silently drop all
>      cursor rendering.  -> patch required if deemed useful

* People who sometimes have to boot X in 'safe mode' (just X and
xterm) because kde/gnome won't start up.