po4a: build failure if perl5 is installed with mismatching variant

[i0ntempest]

By default po4a uses perl 5.30. I have perl5 +5_34 installed and it causes this build failure.

_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_po4a/po4a/work/po4a-0.66" && /opt/local/bin/perl5.30 Build build 
:info:build Created META.yml and META.json
:info:build Unknown format type: pod.
:info:build po4a::chooser: Module loading error: Can't locate Pod/Parser.pm in @INC (you may need to install the Pod::Parser module) (@INC contains: lib /opt/local/lib/perl5/site_perl/5.34/darwin-thread-multi-2level /opt/local/lib/perl5/site_perl/5.34 /opt/local/lib/perl5/vendor_perl/5.34/darwin-thread-multi-2level /opt/local/lib/perl5/vendor_perl/5.34 /opt/local/lib/perl5/5.34/darwin-thread-multi-2level /opt/local/lib/perl5/5.34) at lib/Locale/Po4a/Pod.pm line 14.
:info:build BEGIN failed--compilation aborted at lib/Locale/Po4a/Pod.pm line 14.
:info:build Compilation failed in require at (eval 37) line 1.
:info:build BEGIN failed--compilation aborted at (eval 37) line 1.
:info:build List of valid formats:
:info:build   - asciidoc: AsciiDoc format.
:info:build   - dia: uncompressed Dia diagrams.
:info:build   - docbook: DocBook XML.
:info:build   - guide: Gentoo Linux's XML documentation format.
:info:build   - ini: INI format.
:info:build   - kernelhelp: Help messages of each kernel compilation option.
:info:build   - latex: LaTeX format.
:info:build   - man: Good old manual page format.
:info:build   - pod: Perl Online Documentation format.
:info:build   - rubydoc: Ruby Documentation (RD) format.
:info:build   - sgml: either DebianDoc or DocBook DTD.
:info:build   - texinfo: The info page format.
:info:build   - tex: generic TeX documents (see also latex).
:info:build   - text: simple text document.
:info:build   - wml: WML documents.
:info:build   - xhtml: XHTML documents.
:info:build   - xml: generic XML documents (see also docbook).
:info:build   - yaml: YAML documents.
:info:build Died at Po4aBuilder.pm line 162.
:info:build Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_textproc_po4a/po4a/work/po4a-0.66" && /opt/local/bin/perl5.30 Build build 
:info:build Exit code: 1

Deactivating perl5 while still leaving actual perl5.34 installed will allow it to build.

[i0ntempest]

Related: #64203