quickly make a void chroot in a foreign architecture for testing things in a binfmt-misc context

mkvoidchroot.sh

#!/bin/bash
set -exo noclobber

ARCH="${1:?}"
ROOT="/var/chroot/void-$ARCH"
REPO=https://alpha.us.repo.voidlinux.org/current
if [[ "$ARCH" =~ ^ppc ]] ; then
    case "$ARCH" in
        ppc) REPO=https://repo.voidlinux-ppc.org/current/ppc ;;
        ppc-musl) REPO=https://repo.voidlinux-ppc.org/current/ppc/musl ;;
        ppc64) REPO=https://repo.voidlinux-ppc.org/current/be ;;
        ppc64-musl) REPO=https://repo.voidlinux-ppc.org/current/be/musl ;;
        ppc64le-musl) REPO=https://repo.voidlinux-ppc.org/current/musl ;;
        ppcle) REPO=https://auto.voidlinux-ppc.org/testing/ppcle ;;
        ppcle-musl) REPO=https://auto.voidlinux-ppc.org/testing/ppcle-musl ;;
        *) REPO=https://auto.voidlinux-ppc.org/current ;;
    esac
elif [ "$ARCH" == aarch64 ] ; then
    REPO=https://alpha.us.repo.voidlinux.org/current/aarch64
fi

cat > "$HOME/bin/chroot-void-$ARCH.sh" <<EOF
#!/bin/bash
if [ "\$EUID" -ne 0 ] ; then
    exec sudo "\$0" "\$@"
fi
cd "$ROOT"
mount --rbind --make-rprivate /dev dev/
mount -t sysfs sys sys
mount -t proc proc proc
mount -o bind /tmp tmp/
chroot .
umount tmp sys proc dev/pts dev/shm dev
EOF
chmod +x "$HOME/bin/chroot-void-$ARCH.sh"

sudo mkdir -p "$ROOT/usr/bin/" "$ROOT/etc"
sudo cp "/usr/bin/qemu-${ARCH/armv7l/arm}-static" "$ROOT/usr/bin/"
sudo cp "/etc/resolv.conf" "$ROOT/etc/"

sudo env XBPS_ARCH=$ARCH xbps-install -S -y -r "$ROOT" -R "$REPO" base-chroot pam

sudo useradd -R "$ROOT" -u "$UID" `whoami`