On: Even DJB's code is buggy. (And some others too.)

Ha, thanks! I didn't notice '=' was wrong there, part of me thinks that can actually be common in C (assigning the result of a condition to be further used within the block).

It can be intentional if the right side is a function call.

But something like:

if (errno = 0) { blah(); }

is almost certainly a bug.