preparing for release

[Jim Meyering]

I've pushed a couple of diffs, so that now all tests pass at least on
Fedora 30 using gcc10 and on stock fedora 31.

I know Assaf has been doing a lot of bug triage (thanks again!), so I
will probably make the first snapshot today. I'll have limited time
over the next week or two for bug triage, so if anyone can lend a hand
there, I'd sure appreciate it.

https://debbugs.gnu.org/cgi/pkgreport.cgi?package=sed