Comment # 18 on bug 98238 from Shmerl

I compiled the latest Mesa master (git-2ab2be092d) which includes the recent
fix from Marek:
https://cgit.freedesktop.org/mesa/mesa/commit/?id=59c5da40ed2c6c56e29b562c2ee2c8705f28738b
and the bug is mostly gone, but it still happens in few areas for example on
the brick city walls and gates in Flotsam.