On 2020-06-07 21:30, Rich Freeman wrote:
> On Sun, Jun 7, 2020 at 2:56 PM n952162 <n952162@web.de> wrote:
>
>> The emerge that I used was this:
>>
>> emerge -auDv --verbose-conflicts --changed-use --keep-going --with-bdeps=y --changed-deps --backtrack=100 @system
> Yeah, you might have to include the other packages that need readline
> if portage complains.
>
>

This, indeed, seems to have been the magic.

By specifying *both* @system and @world, two of my machines that I
worried were lost-causes are now updating - hundreds of packages, but
that's okay, I've been pulling my hair out for months.