bug#25552: 26.0.50; load cl unintendedly

[Glenn Morris]

Bill Wohler wrote:

> I don't have any objections if it runs on all supported versions of
> Emacs that we support (a conversation we should probably have again
> since we've had an Emacs release).
>
> I'm happy to say we support the version of Emacs in Debian stable, which
> is 24 and is what I'm running. I'll test the patch this weekend and reply.

I see that Debian stable ships Emacs 24.4, which includes cl-lib (so
does 24.3, which is 4 years old). It's fine to load cl-lib at runtime.
So if you were willing to make a larger change (cl to cl-lib), you can
have code which is simpler going forwards (no need for mh-require-cl etc).
cl-lib is also available from elpa.gnu.org for Emacs older than 24.3.

Separate from the above:
i) I think all uses of mh-require should be placed within eval-and-compile
(the compiler does this automatically for plain "require", but does not
know to do it for mh-require).

ii) If you make that defun-mh change, I'm guessing there will no longer
be a need for mh-gnus to be no-byte-compile.