The switch statement given/when was introduced in Perl 5.10 and got

The switch statement given/when was introduced in Perl 5.10 and got
experimental in Perl 5.18.  So we see warnings in the tests.
given is experimental at funcs.pl line 62.
when is experimental at funcs.pl line 63.
Just suppress this type of warnings for now.  If Perl will disable
smart match, the simple regression code still works.  If they will
choose to remove given/when, we can fix it later.
Discussed with and OK andre@ afresh1@