gEDA-dev: Double buffering in PCB

[DJ Delorie]

> I've not noticed any obvious improvement in performance, nor any
> obvious redraw artifacts (I presume PCB double buffers internally,
> however I've not looked! The PC I'm using is quite fast though, and
> I never found GTK PCB slow. Is it useful for someone with a slower
> machine available to see if this helps?

Compare with the lesstif build, which uses explicit double buffering
only.

You can also test some things by forwarding your X connection to a
remote machine.