Generated C code consistency, part 2: giving up to gain victory

[nikodemus]

PR #822 is just running its tests now, but they already passed for me locally.

I did a bit of analysis in the related issue (#755), and turns out I was too ambitious: see analysis there, but the short version is that a "one-stage" bootstrap would be a real headache to keep consistent, and a "two-stage" bootstrap was already consistent.

...so I decided to give up on the one-stage goal and be happy with what we have. A philosophical conclusion. 😀