This allows us to avoid the warnings from bash-4.4 about null bytes in
command substitutions.
If you have separate /usr, are not using an initramfs, and have a file
called /proc/self/environ on your root file system, this will break.
X-Gentoo-Bug: 594534
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=594534