I was going to comment that any sort of script that you are using in multiple environments probably should have all of the paths completely written out. I usually try to do this myself as I have gotten burned by binaries from unexpected paths on new systems a number of times.
But then I realized that the point of this project is to make it easy to write scripts that can be used on multiple OSs... and that is going to make fully-qualified paths possibly a nightmare. Anyone know if these get put at `/bin/`?
Sounds like a case for GNU Autoconf and ./configure.
On nixos they're not, there's a single executable in /bin -- /bin/sh, and a single executable in /usr/bin -- /usr/bin/env