register-immutable-system -> (setf system-mutable-p)

[Attila Lendvai]

the export entry in the package was not renamed, it still exports
REGISTER-IMMUTABLE-SYSTEM.

-- 
• attila lendvai
• PGP: 963F 5D5F 45C7 DFCD 0A39
--
“You can get love only from a free agent whose uniqueness is respected
by you, whose freedom is respected by you. It is out of the freedom of
the other that this moment of love has happened. Don’t destroy it by
trying to possess, by trying to hold, by creating a legal bondage, a
marriage. Let the other be free, and remain free yourself. Don’t let
anybody else possess you either. To possess or to be possessed, both
are ugly. If you are possessed you lose your very soul.”
	— Osho (1931–1990), 'From Darkness to Light' (1985)