plperl and perl 5.38

Perl 5.38 has landed in Debian unstable, and plperl doesn't like it:

diff -U3 /home/myon/projects/postgresql/pg/postgresql/src/pl/plperl/expected/plperl_elog_1.out /home/myon/projects/postgresql/pg/postgresql/build/testrun/plperl/regress/results/plperl_elog.out
--- /home/myon/projects/postgresql/pg/postgresql/src/pl/plperl/expected/plperl_elog_1.out 2023-07-24 12:47:52.124583553 +0000
+++ /home/myon/projects/postgresql/pg/postgresql/build/testrun/plperl/regress/results/plperl_elog.out 2024-01-12 10:09:51.065265341 +0000
@@ -76,6 +76,7 @@
RETURN 1;
END;
$$;
+WARNING: could not determine encoding for locale "C.utf8": codeset is "ANSI_X3.4-1968"
select die_caller();
NOTICE: caught die
die_caller
diff -U3 /home/myon/projects/postgresql/pg/postgresql/src/pl/plperl/expected/plperl_call.out /home/myon/projects/postgresql/pg/postgresql/build/testrun/plperl/regress/results/plperl_call.out
--- /home/myon/projects/postgresql/pg/postgresql/src/pl/plperl/expected/plperl_call.out 2023-10-17 09:40:01.365865484 +0000
+++ /home/myon/projects/postgresql/pg/postgresql/build/testrun/plperl/regress/results/plperl_call.out 2024-01-12 10:09:51.413278511 +0000
@@ -64,6 +64,7 @@
RAISE NOTICE '_a: %, _b: %', _a, _b;
END
$$;
+WARNING: could not determine encoding for locale "C.utf8": codeset is "ANSI_X3.4-1968"
NOTICE: a: 10, b:
NOTICE: _a: 10, _b: 20
DROP PROCEDURE test_proc1;

Same problem in 17devel and 16. (Did not try the older branches yet.)

Christoph