Re: Proposal for enabling auto-vectorization for checksum calculations

> You can see the failure at the artifacts ->
> 'log/tmp_install/log/install.log' file on the CI web page [1].
>
> If you want to replicate that on your local:
>
> $ ./configure --with-llvm CLANG="ccache clang-16"
> $ make -s -j8 world-bin
> $ make -j8 check-world
>
> should be enough. I was able to replicate it with these commands. I
> hope these help.
Thanks so much for helping me figure this out!

Okay, I've determined that versions of LLVM/Clang before 19 crash when
compiling this patch for some reason; it seems that both make
check-world and make install will crash with the affected LLVM
versions.
Unfortunately, what matters seems to be the version of the linker/LTO
optimizer, which I don't think we can check at compile time.
I added a check for Clang>=19 which works at preventing the crash on my system.
I think it's possible some unusual combination of clang/LLVM might
still crash during the build, but I think this is a reasonable
solution