ZDoom

I am presently trying to figure out what is causing this crash in order to produce a minimal example for it - but in the meantime, here's the steps to reproduce:

> load tgrdm3.pk3 (aka Morgenstern)
> enter "map start dm" in the console
> crash!

This appears after the 'goto clearfog' removal in this commit - https://github.com/coelckers/gzdoom/com ... 9c6e030df5

It crashes when drawing the walls. (At first the voxel code was suspect, but that turned out not to be the case, it was specifically the clearfog commit that made this crash appear)

EDIT: One more bit of info - this appears to be related to 3D floors. Setting "r_3dfloors false" before entering the Start map prevents the crash.

Okay, I'll take a look. I probably failed at not'ing one of the checks.

Committed a fix for this.