What's wrong with Hegel? (Foucault's _Archaeology..._)

By the end of "discourse on Language_, Foucault seems to be
going mad himself over the impossibilty of ever having
a philosophy that isn't Hegelian...(_Archaeology of Knowledge_, p. 236).

Why is he so upset with Hegel?

Is the point of the whole study of madness in _Archaeology..._ to
refute Hegel's methods and philosophy?

I'm curious as to why Foucault feels this strong antipathy,
frustration, and helplessness regarding Hegel.

Could someone enlighten me?

Thanks,

Glo