This is kind of a "release". Figured I would share some binaries so people don't have to go through all the build gyrations. The pidgrid-rpi binary works on my DevTerm running 5.10.60-rockchip64 on aarch64. The plain pidgrid binary is for x86_64. I'm no C expert so YMMV.
You should be able to copy the binary into /usr/libexec/xscreensaver and then copy an existing line in your $HOME/.xscreensaver file to make it visible to xscreensaver-demo.