When running 'dzil build', it fails with the output:
[Run::BeforeArchive] executing: sed -i -e'/^=head1 AUTHOR/i=for readme start\n\n' Crypt-PKCS10-1.4/lib/Crypt/PKCS10.pm [Run::BeforeArchive] sed: 1: "Crypt-PKCS10-1.4/lib/Cr ...": invalid command code C
This appears to have been introduced between V1.4_04 and V1.4.