$^X, but not getting it right. I'll wait to see if Jos has a fix.
p4raw-id: //depot/perl@29381
### test 'requires' ###
-{ my %list = map { $_ => 1 } requires('Carp');
+SKIP:{
+ skip "Depends on \$^X, which doesn't work well when testing the Perl core",
+ 1 if $ENV{PERL_CORE};
+ my %list = map { $_ => 1 } requires('Carp');
my $flag;
$flag++ unless delete $list{'Exporter'};