gEDA-dev: mis-drc'd arcs

[DJ Delorie]

> Ahh the troubles we can get into. So the recent board has one analog
> section where I flipped the schematic hierarchy pins with the
> symbols hierarchy pin allowing me to reverse the +5 and -5 analog
> voltages. I love it when polorized caps go pop.

When I put LEDs, diodes, and other polarized parts on, I usually look
at the schematics, look at the PCB layout, and decide which way I
*think* it should go.  Then I compare that with the silkscreen.  If
they match, on it goes.

I did have one board that I did a 180 degree rotation of an AND gate.
That swapped the power pins (single gate chip).  A horizontal flip
would have been the right thing to do.  No pop, just smoke.