Stefan, can you take a look at this?

I think I now understand why there are slight differences in the
loaddefs.el file generated by my declare-based, eager-loading patch.
There is a /bug/ in the fallback "list 3" generation of autoloads,
leading to incorrect autoload statements being written out.

The `INTERACTIVE' arg to `autoload' is supposed to be formed as follows:

  If INTERACTIVE is a list, it is interpreted as a list of modes the
  function is applicable for.

The current code mistakenly injects the actual ARG-DESCRIPTOR list into
the autoload file, for those (few) macros which are not expanded but
fall through to list 2, possibly just `cl-defun's.  You might see for
example the full `(let...` descriptors for `erc` in your loaddefs.el
file.

That's a bug I believe, and will presumably mess with the mode-specific
M-S-x type functionality. So by expanding more eagerly with `(declare
(autoload macro-expand))', this bug was "eliminated".  The attached
fixes it for any cases which still use fall-through to list 2.

Thoughts?