dh_setup_copyright: Save source packages for external files and shlibs
https://phabricator.apertis.org/T9756
Draft because it depents on dwarf2sources!14 (merged).
🟠 v2026dev0 entered Soft Code Freeze/Hard Feature Freeze, only bug fixes will be accepted • schedule
https://phabricator.apertis.org/T9756
Draft because it depents on dwarf2sources!14 (merged).