Building the OS is now as simple as running `make` on a Gentoo system.
Interestingly, when `make` is executed as a (grand)child process of
another `make` process, it always prints an `Entering directory ...`
message. This breaks the `make kernelversion` command, by adding
extraneous text to the output.
When running inside a rootless Podman container on a SELinux-enabled
host, the `patch` command fails because it cannot copy SELinux labels
from the original file to the patched file. This only happens patching
files that are located in a bind mount.
