> As for test_ttk and such, those that have a third-party dependency are
> still optional no matter what. This change is **only** for modules we
> expect to always build on certain platfoms (e.g., winreg under Windows
> or crypt on UNIX systems).

Ah, thanks for pointing that out to me. That's certainly better than
what I thought :)

> I mean do we really think ctypes is optional at this point?

Why wouldn't it be? It doesn't offer any essential functionality, and
most applications and libraries certainly don't depend on it.
It's far more optional than zlib (which a bunch of stdlib functionality
relies on) IMO.

What's more, standard C isn't enough to compile ctypes (as you witnessed
with LLVM). So, really, making absence of ctypes a failure sounds too
severe to me.