Objective-C, Swift: how to set up a local dev env?

I am playing around in trying to set up local dev environments for all the CG-supported languages to be able to run the CG solo puzzle solutions also locally on Windows and/or on Ubuntu on WSL. (This is in support of my local batch test runner cgtest.)
I succeeded in all languages except Objective-C and Swift, so would be glad to have some advice on these.

(1) I have vanilla Clang 17.x up and running both on Windows and on Ubuntu and it works for c or c++, but how to make it work for objective-c? Where to get the needed library #include <Foundation/Foundation.h> from? How to invoke clang via cli correctly for objective-c?
Note: if it is better to do it with gcc, it is also fine for me, I have gcc 13.1 both on Windows and Ubuntu, working already for c,c++ and even fortran.

(2) Any advice how to make the Swift compiler work (NOT starting by “buy a Mac”?)

Edit: Clojure part deleted, solved with help by mji on Discord