=> https://bugs.archlinux.org/task/46169


Download bootstrap chroot
=> http://quantum-mirror.hu/mirrors/pub/archlinux/iso/2021.11.01/archlinux-bootstrap-2021.11.01-x86_64.tar.gz
Extract it somewhere.

Final boot script.
Important!!! Run with `sudo -E`. The "-E" is important. Or just hardcode the path to your home directory.
```
#!/bin/sh
set -ex

cd "$(dirname "$0")"
mount --bind root.x86_64 root.x86_64
mount -o bind "$HOME" root.x86_64/home/user/host-home

# delete these two if you are not using Guix, or modify them if you are using Nix
mount -o bind,ro /gnu/store root.x86_64/gnu/store
mount -o bind,ro /var/guix root.x86_64/var/guix

bash root.x86_64/bin/arch-chroot root.x86_64 /bin/env -i bash -l

# again, delete them
umount -l root.x86_64/var/guix
umount -l root.x86_64/gnu/store

umount -l root.x86_64/home/user/host-home
umount -l root.x86_64
```

First time, on the host system:
```
# write down this number, it will be important
echo $UID

sudo mount --bind root.x86_64 root.x86_64
sudo bash root.x86_64/bin/arch-chroot root.x86_64 /bin/env -i bash -l
```

First time setup inside guest:
```
# enable some mirrors
sed -i 's/^#\(.*\.hu.*\)/\1/' /etc/pacman.d/mirrorlist
# set up timezone
ln -s /usr/share/zoneinfo/Europe/Budapest /etc/localtime
# initalize package manager
pacman-key --init
pacman-key --populate archlinux
# install development packages
pacman -Syu --needed git base-devel
# optional if you are using Guix, otherwise not really:
pacman -S base
# (if you are using Guix or Nix, you can just mount their store and use their packages)
# create store mount point
mkdir -p /gnu/store
mkdir -p /var/guix
# create a non-root user. the UID thing is important, it lets you share your host's home directory in the guest.
useradd -m -u $UID_OF_HOST_USER user
# optional: ignore all security precautions and enable passwordless sudo for this user?
# maybe don't do this?
echo 'user ALL=(ALL) NOPASSWD: ALL' >> /etc/sudoers
# alternatively, add a password
usermod -aG wheel user
passwd user
echo "%wheel ALL=(ALL:ALL) ALL" >> /etc/sudoers
# change to a login shell of the new user
su -l user
# create host home mount
mkdir ~/host-home
# install yay
git clone https://aur.archlinux.org/yay.git
cd yay
makepkg -si

# now you can install anything, like, say, Infer.
yay -Sy infer

# link to host guix. ignore if your host system isn't Guix.
(cd ~/.config; ln -s ../host-home/.config/guix ~/.config/guix)
ln -s host-home/.guix-profile ~/.guix-profile/
```