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