MacPorts openssl versus Perl
This is only of interest to Mac users who link their Perl against MacPorts code, but if you are such a person, you may find this useful.
This morning I found that Perl code that used LWP::Protocol::https was failing, but only when run by the test harness.
After some flailing around I managed to track this to the fact that I had just updated MacPorts, and taken openssl from 1.0.2f_0 to 1.0.2g_0. I still do not know the precise cause of the failure, but it was exposed by the fact that the test harness (whether ExtUtils::MakeMaker or Module::Build) set PERL_DL_NONLAZY=1.
Downgrading to the old openssl did not fix the problem of course, but made the symptoms go away. The short version of the procedure is
$ sudo port activate openssl @1.0.2f_0
For details on downgrading a port, see https://trac.macports.org/wiki/howto/InstallingOlderPort