xf86UDelay was used - removal breaks drivers

[Nix]

On 7 Nov 2009, Alan Coopersmith stated:
> I know we have -ast users, since that's the remote console in a number
> of current Sun servers (both SPARC & x64) - but they get stable builds
> shipped, not git head.

Also non-Suns: I bought an x86_64 server in April this year that has an
ast. But the graphical console is an emergency thing for me and probably
for most users (ast hardly being a speed demon): I simply haven't
started it in a month or so, so wouldn't have noticed the breakage yet.