[Freeciv-Dev] (PR#8788) gui-gtk overview crash

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=8788 >

If you click along the right side of the overview, the coordinates 
passed to the overview code will be "outside" of the overview range, 
resulting in an unreal tile being found.  This will trigger an assertion 
(or random bad results if you compiled with NDEBUG).

Oh, this only applies with maps that don't have TF_WRAPX.  I don't think 
it occurrs in the vertical direction or we'd have seen it long before.

The gtk client should not pass values outside the range of the overview 
width and height.

jason