Comment 15 for bug 1437930

If I'm reading this back trace correctly, it appears that something in a
std::list is being freed from memory more than once. Here is the error
I get in gdb on a 64 bit build against boost 1.57 on windows:

#0 0x00000000109c9320 in std::list<boost::polygon::point_data<int>,
std::allocator<boost::polygon::point_data<int> > >::begin
(this=0xfeeefeeefeeefeee)
    at C:/msys64/mingw64/include/c++/4.9.2/bits/stl_list.h:772

On 3/31/2015 3:16 PM, jean-pierre charras wrote:
> Again, this is a bug in boost::polygon which happens rarely, and
> *depends on the shape of polygons*
>
> Commit 5548 slightly changed the shape of polygons which approximate a circle (changed the number of segments).
> This board crashes, and perhaps boards which previously crashed in 3D viewer are now working.
>
> You easily verify by changing the clearance of the zone on the back
> side, i.e. the shape of polygons, the crash does not happen.
>
> The way the circles are approximated will be changed soon, but it will
> not fix anything, although this board will not crash anymore.
>