Quicklisp should perhaps drop the antique ASDF it bundles

[tfeb]

The fallback ASDF (2.26) bundled with Quicklisp is too old to build many projects.

I understand the desire not to update it to a newer version, but I think that rather than distributing something that is explicitly broken (if you, for instance, install QL on an implementation which does not have ASDF, then (ql:quickload ...) will just break in mysterious ways for many QL-provided systems & this does not give a good impression) it would be preferable to detect that there is no ASDF, give a reasonable error, and bail out at setup time. I'd rather have a setup fail than have it 'succeed' but in fact be broken.

Obviously this is an opinionated issue: if you disagree feel free to close it!

If you agree I'd be willing to put in some work & a PR to excise the old ASDF version.

[link2xt]

Current fallback ASDF version is 3.2.1 since https://github.com/quicklisp/quicklisp-client/commit/313ffa73324f516874422e4932ef3777622bea6a

I understand the desire not to update it to a newer version

Was there any reason not to update before?