0.56: flaky behavior of examples/02-multi-simple.pl on Amazon Linux 2023 instances

[ifettich]

First run of it gives:
...
$ perl 02-multi-simple.pl
Operation was aborted by an application callbackFatal glibc error: pthread_mutex_lock.c:95 (___pthread_mutex_lock): assertion failed: mutex->__data.__owner == 0
Aborted (core dumped)
...

Second run gives
...
$ perl 02-multi-simple.pl
callback function is not set
Operation was aborted by an application callbackpanic: MUTEX_LOCK (22) [curl-Share-c.inc:33] during global destruction.
...
Then, a few runs in row it works just fine... And then again a failure or two, and a longer list of succeeds.

This happens in similar ways with the 'standard curl' rpm package installed from the Amazon Linux 2023 repository, as with curl 8.7.1 installed from git and compiled against. Other people reported that it also fails with libcurl 8.9.1.
As far as could look into it, it seems to be something related to DNS (some missing, but needed initialization?) - the error comes up before there's any 'real work' started by curl.

Thank you!