Thanks for the responses guys, lots of stuff for me to look into. I'll probably not go the straight up Windows route; I have a Windows PC, so I could follow along if I like - and I probably will as I have zero windows programming experience - but honestly I'm just plain interested in learning about how to develop this way for OS X.
drjeats
If you're just looking to learn without the clutter of Xcode, it's possible to follow the SDL2 "Handmade Penguin" tutorial. For any major differences, you can cross-reference the OS X repo. Most things, like opening windows and filling an audio buffer should work mostly the same on OS X as it does on Linux.
You need to install Xcode though, that's where you get your compiler! Also your debugger frontend. It's not as good as Visual Studio (the expression list is bad and Apple should feel bad), but it's better than only having the lldb prompt.
Thanks for that, I'll check out HH Penguin. I take it the fact it uses SDL2 means it's not in the same vein of 'zero libraries' as HH Windows? Not necessarily a dealbreaker for me, but it would be cool to understand the very basics of what SDL is doing when I ask it to create a window, say. In fact, when Casey gets to the point where he's making the platform layers for linux/osx/etc., will he be using SDL or will we get a similar crash course in 'here's how you get the OS to give you a window and how to draw to that window'? Just in case he's answered that elsewhere and I've missed it.
Cheers guys, thanks for answering my newb questions!