contrib/fuzz/pyutil.h

util: extract compression code in `mercurial.utils.compression`

The code seems large enough to be worth extracting. This is similar to what was
done for various module in `mercurial/utils/`.

Since None of the compression logic takes a `ui` objet, issuing deprecation
warning is tricky. Luckly the logic does not seems to have many external users.

#include <Python.h>

namespace contrib
{

void initpy(const char *cselfpath);
PyObject *pyglobals();

} /* namespace contrib */