Tested with no result with auto all fits on Fedora 32 only and planning on testing next on Fedora 37:

   0010-TMP-add-flto-to-cinelerra-Makefile.patch

How do I test this?:

   0011-EXPERIMENTAL-try-to-init-two-variables-to-0-in-gloat.patch

well, in theory (I hoped) 0010 should trigger crash on "auto fit autos" and 0011 should fix it. But because it does not crash for me on termux and I not tested it on desktop Slackware yet ... whole thing might be moving in wrong direction.

Thanks for the explanation.  I have booted Fedora 37 (because that is where it crashed for Jin) and built it using 0010 with the added flto flag.  It still does not crash.    I no longer have Fedora 36 available and am not planning on getting it back.  Without being able to reproduce the crash, it really is practically impossible to fix.  I suspect you already looked at their reported compilation flags, but I will try some of their more weird ones if I can figure out how (like -Werror=format-security) which must be like how you added -flto.  Stay tuned.