Fixes build of pkgsMusl.systemdMinimal (and pkgsMusl.systemd if combined with
other fixes).
These patches are applied conditionally on purpose: They are not checked to
be properly guarded. They should not block future systemd upgrades.
Also see the original RFC section around musl systemd:
https://github.com/NixOS/rfcs/blob/master/rfcs/0023-musl-libc.md#systemd
