Comment 17 for bug 1926355

Another variant of the problem that I mentioned in comment #15. An ubuntu user just reported it on IRC:

$ apt install clang
The following packages have unmet dependencies:
 clang : Depends: clang-10 (>= 10~) but it is not going to be installed

That apt message is misleading, as the underlying error is the libc6 version:

$ dpkg -l | awk '$3=="2.31-0ubuntu9.3" { print $2, $3 }'
libc-bin 2.31-0ubuntu9.3
libc-dev-bin 2.31-0ubuntu9.3
libc6:amd64 2.31-0ubuntu9.3
libc6:i386 2.31-0ubuntu9.3
libc6-dbg:amd64 2.31-0ubuntu9.3
libc6-dev:amd64 2.31-0ubuntu9.3
locales 2.31-0ubuntu9.3

To be able to install clang, all these packages would have to be downgraded manually, with:

$ sudo apt install $(dpkg -l | awk '$3=="2.31-0ubuntu9.3" { print $2"=2.31-0ubuntu9.2" }')

The following packages will be DOWNGRADED:
  libc-bin libc-dev-bin libc6 libc6:i386 libc6-dbg libc6-dev locales

But we can't expect thousands of Ubuntu users to run that command manually.
Please do upload a new glibc 2.31-0ubuntu9.4 version, to amend this issue...