Re: PL_stashcache, or, what's our minimum Perl version?

I wrote:
> So the question is, does anyone care? I wouldn't except that our
> documentation appears to claim that we work with Perl "5.8 or later".

BTW, what actually says that is installation.sgml:

<application>Perl</> 5.8 or later is needed to build from a Git checkout,
or if you changed the input files for any of the build steps that
use Perl scripts. If building on Windows you will need
<application>Perl</> in any case. <application>Perl</application> is
also required to run some test suites.

Strictly speaking, there is no statement anywhere (AFAICT) about what
Perl versions PL/Perl works with.

As an experiment, I built from a "make maintainer-clean" state using
that 5.8.0 install, and it worked. So indeed installation.sgml's
statement is correct as far as it goes. But I dunno what the situation
is for the MSVC build scripts. I did not try the TAP tests either.

A look in the buildfarm logs says that the oldest Perl version we're
actually testing is 5.8.6 on prairiedog. (castoroides/protosciurus
have 5.8.4 but they are not building --with-perl, so that only
exercises the build scripts not plperl; they're not doing TAP either.)
I only looked into configure.log results though, so I'm not sure
about the Windows critters.

I kinda suspect we're not actively testing non-MULTIPLICITY builds
either. The 5.8.7 test I just ran was with a non-MULTIPLICITY build,
so the case doesn't seem actively broken, but I doubt there is any
buildfarm coverage. I wonder if it'd be worth getting the buildfarm
to log the output of "perl -V" so we could get a clearer picture
of what's being tested.

regards, tom lane