Thanks for pointing it out.

Indeed, OpenBSD’s and NetBSD’s `env` does not support `-S`. DragonflyBSD does (as expected).

Solaris as pointed out by the first link doesn’t even support more than one argument in the shebang so no surprise that its `env` does not support it either. Neither does IllumOS (but not sure about the shebang handling)

Also, it doesn't work on Busybox either (e.g. on Alpine Linux).