the Thread extension hasn't been built.
p4raw-id: //depot/perl@8523
delete_by_prefix('File::Spec::'); # File::Spec's domain
$Core_Modules{'File::Spec::Functions'}++; # put this back
-delete_by_prefix('Thread::') unless $Config{extensions} =~ /\bThread\b/;
+unless ($Config{extensions} =~ /\bThread\b/) {
+ delete $Core_Modules{Thread};
+ delete_by_prefix('Thread::')++;
+}
delete_by_prefix('unicode::');
$Core_Modules{'unicode::distinct'}++; # put this back