Gitian (windows) results not deterministic when run on aarch64 #17468

Gitian can be run on aarch64, see #17409. However, the results are not deterministic.

I can't upload the full result, so here is the diffoscope (remove the .docx extension to extract):

diffoscope.txt.tar.xz.docx

Depends seem to match. Here is the diffoscope html for the binaries:

diffoscope.html.txt

I did a second build of windows on aarch64 and at least the results match the previous aarch64 run

Which gcc cross-compiler package are you using on aarch64?

g++-8-x86-64-linux-gnu or g++-7-x86-64-linux-gnu? I guess the latter, because the descriptor uses the default native gcc compiler on bionic?

on aarch64:

$ x86_64-linux-gnu-g++-7 --version
x86_64-linux-gnu-g++ (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
$ x86_64-linux-gnu-g++-8 --version
x86_64-linux-gnu-g++-8 (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0

on amd64:

$ gcc --version
gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0

(it's slightly inconsistent that we use gcc 7 for x86 builds and gcc 8 for the rest, but okay)

Edit: ahh, you're comparing windows, that would be using exactly the same package and libraries, I suppose!

Let's focus on guix