> I've replaced them with SAFE_ALLOCA now.  Arthur, please see if you
still get C stack overflow.

Thus far, I pulled and compiled with -O2 -mtune=native; It does not end
in C stack overflow, but it does crash Emacs.

On first run, there was native compiler interfering, so I restarted Emacs, let
the native compiler do what it wants to do, and than restarted a new and
tried, and I get the same problem: memory exhaustion, when Emacs takes
somewhere around 12 gig. I have 32 gig ram in this machine; it is the same
computer from a couple of years (or more?) ago when Emacs was eating
all 32 gig on gnu/Linux).

Now, Emacs is taking about 12 gig when it reports memory exhaustion. You
can see from the screenhots, it is going up, and than ~12 or immidiately before
it reports memory exhausted in Messages buffer. Interested thing, the graphic
driver also crashed, so I couldn't take the screenshot of the last time, I don't know
if the changed resolution is visible on a screenshot. The process manager reports
only about 60% of memory usage, so I am not sure why it crashes, but felt like
back in time of Windows 98; it didn't help to restart explorer or change desktop
settings, I had to restart the system 🙂. On Arch, I was able to switch to
another tty, kill Emacs and restart X11, and everything was fine again.

I will rebuild also in debug mode.