I used to work in the same industry. We used linux and gcc, so we could, and did, produce fully deterministic builds. Actually the output was fully deterministi

I used to work in the same industry. We used linux and gcc, so we could, and did, produce fully deterministic builds. Actually the output was fully deterministic disk images. I did one iteration of the build system, mostly making it such that any host could build it deterministically. This was years ago so it was just chroot that started with a skeleton + GCC and procedurally built the things it needed to build the outputs. Was fairly straight forward, just an extremely short patch here and there, a 1000 line Xorg Makefile for staging Xorg builds. If I was doing it again I'd consider reusing a package manager, but each components Makefile was pretty concise. My trusty sidekick was a script that xxd'd two files into pipes that it opened using vimdiff. Build took an hour or so, however.