build-depend on autoconf-archive and rm convenience copy in orig.tar.gz?

[Thomas Koch <thomas@koch.ro>]

I searched but apparently this has not yet been discussed anywhere below lists.debian.org.

My package ships two convenience copies from autoconf-archive in it's m4 folder. Should I

a) leave these files and add the corresponding data to d/copyright or
b) leave these files and don't bother about d/copyright or
c) remove these files and add build-depend on autoconf-archive, linking the files before dh_autoreconf?

Apparently I'm not the only one with uncertainty here:
https://bugs.debian.org/949119

Thanks for your guidance, Thomas