CreationDate in PDF metadata breaks reproducible builds

Greetings,

I would like to report that the CreationDate value that is set in the PDF file changes at each run. This is problematic because that makes it impossible to run FOP in the context of reproducible builds (see https://wiki.debian.org/ReproducibleBuilds).

Would it be possible to create an option to set that date value manually or some equivalent solution to this problem ?

Thank you so much for your work on FOP !

Regards,
Filippo