gEDA-user: DRC/rat quirks

[DJ Delorie]

>    For instance, you must turn it off if you are placing a via to connect 
> traces to finish off a rats nest, even if the rats are displayed properly.  

Ok, I can reproduce this.  PCB expects you to do something else.  What
it wants is for you to draw the line off the first pin, change layers,
and continue drawing lines.  It puts in the vias for you whenever you
change layers.  You should be able to connect to vias that are already
connected to the net through other lines, though.  It's just totally
unconnected vias it's blocking.