gnuplot patch to speed up cygwin implementation by 2x

[Jim Kleckner]

Jim Kleckner wrote:
> The attached patch for gnuplot speeds it up on Cygwin
> by around 2.5x due to unbuffered reads for all file types.
>
> I will submit it upstream as well.
>
> See this link for the original discussion:
>  http://tinyurl.com/6c4sse
>  http://thread.gmane.org/gmane.comp.graphics.gnuplot.devel/2189/focus=2207 
>

I withdraw that patch.

I tried nailing the places where setvbuf and setbuf were called on stdin
but that no longer works to eliminate the very high kernel/system time
overhead seen with pipes.

Instead, I'll figure out how to eliminate the pipes in my toolchain, unless
someone has a suggestion on where to look.