Ok, I have to correct myself:
Compiling any C/C++ project on Windows is an absolute clusterfuck!
I've now almost spent more time trying to compile my program for Windows than writing the actual code for it - let that sink in!
Whoop! It compiles now on Windows! 
You'll never guess what the #error was...
...on my Windows machine I had a file sync program running in the background, which apparently tripped up the compilation process (the program to compile was in a folder that had been under sync)!
Once I moved the program out of this folder, it all compiled fine!
Holy cow! 🤯
Unfortunately, my program doesn't seem to work on #Windows yet. It just gets stuck after passing audio to #Whisper. 😢