I agree with you. Maybe the better question is why does anyone think it shouldn't compile? And then we can ask how much programming history they know.

I think it's useful to know how C compilers, the C specification and C coding styles have evolved over the years. For one, it helps put some of the arguments for/against certain styles and syntax in perspective.

In short, make an effort to learn from history before you make the minimal effort required to learn from a contemporary forum like stackexchange.