> Rust -- say goodbye to cross-compiling, but if you stay away from OS provided libraries, you are kind of covered;
What? Rust can cross compile perfectly fine.
> C / C++ -- certainly possible, but you'll need on retainer a UNIX graybeard, or at least an autotools-foo master;
If you write C and don't know how to cross compile your code you shouldn't be writing it.
> Python -- you're already covered, just read the zipapp documentation;
Python actually can't cross build (reliably).
> Java -- possible, but you'll need a startup script to just call java -jar some-tool.jar; (also not a good fit for short-lived tools, mainly due to startup times;)
Use GraalVM.
What? Rust can cross compile perfectly fine.
> C / C++ -- certainly possible, but you'll need on retainer a UNIX graybeard, or at least an autotools-foo master;
If you write C and don't know how to cross compile your code you shouldn't be writing it.
> Python -- you're already covered, just read the zipapp documentation;
Python actually can't cross build (reliably).
> Java -- possible, but you'll need a startup script to just call java -jar some-tool.jar; (also not a good fit for short-lived tools, mainly due to startup times;)
Use GraalVM.