Greetings!
I can confirm that Clang handles the stack alignment issue with AVX-enabled builds but GCC does not.
Using the following:
1.) https://github.com/mstorsjo/llvm-mingw/releases/tag/20251216
2.) Removing the AVX check in util_bit.h to allow compilation
AVX does indeed work without a segmentation fault.
I recommend adding a check to util_bit.h to explicitly check for Clang and allowing the build on AVX-enabled platforms.
Gemini was right!