plperl: update ppport.h to Perl 5.34.0.

plperl: update ppport.h to Perl 5.34.0.

Also apply the changes suggested by running
perl ppport.h --compat-version=5.8.0

And remove some no-longer-required NEED_foo declarations.

Dagfinn Ilmari Mannsåker

Back-patch of commit 05798c9f7 into all supported branches.
At the time we thought this update was mostly cosmetic, but the
lack of it has caused trouble, while the patch itself hasn't.

Discussion: https://postgr.es/m/87y278s6iq.fsf@wibble.ilmari.org
Discussion: https://postgr.es/m/20220131015130.shn6wr2fzuymerf6@alap3.anarazel.de