For the sake of other readers: note that it is not the build system that
employs the |wall| program. (That would be bizarre.) It is the
|shutdown| program, at runtime, as described in its manual. This is not
a requirement specific to the nosh toolset's |shutdown| program. The old
|shutdown| program in FreeBSD and OpenBSD has the same requirement, for
example, as did the |shutdown| program in 386BSD. Using the |wall|
program to do its job rather than duplicating (a fork of) its code into
|shutdown| (which the van Smoorenburg
|shutdown| programs all have) has a long history in the Unix world.
The |wall|(1) program is available in Void's 'standard'
Because that's what nosh's build system and executables are going to
expect, as far as I know.