- added bind mount of /dev /proc and /sys into target rootfs
- removed missing kmscube dependency
- added missing required build tools (flex, bison, libssl-dev)
- removed auto-delete of target rootfs in mkuserland.sh build step (use cleanup.sh instead!)
- added auto-confirm to package installation and changed apt to apt-get (which is still recommended for scripting; apt is more a human CLI tool)
Tested with fresh install of Ubuntu 20.04 Server
For the build about 15 GiB free disk space is necessary on top of a fresh Ubuntu installation.