gEDA-dev: Checking for mm vs. mil display modes in PCB

[DJ Delorie]

> Interesting.  The HID seems to know, at least in the GTK version,
> because it has the mil/mm selection button on the top right and the
> various status displays show the mil or mm units.  Do you think
> there is a way to detect that display option from the core?

Right, that's the "current mode" flag.  Settings.grid_units_mm

The catch is that you can toggle that flag WITHOUT changing the actual
grid.  For example, if you have a metric grid but want to measure mils
between parts, you'd switch to mils, measure, switch back to mm.