I have tested app-text/xournal-0.4.8.2016 on ppc64 and it works
Sounds good, ppc64 please do. (Though this package is not really developed anymore. Maybe try xournalpp too?)
Looking good on ~ppc64. # cat xournal-792105.report USE tests started on Mi 14. Jul 22:39:17 CEST 2021 FEATURES=' test' USE='' succeeded for =app-text/xournal-0.4.8.2016 USE='-pdf -vanilla' succeeded for =app-text/xournal-0.4.8.2016 USE='pdf -vanilla' succeeded for =app-text/xournal-0.4.8.2016 USE='-pdf vanilla' succeeded for =app-text/xournal-0.4.8.2016 USE='pdf vanilla' succeeded for =app-text/xournal-0.4.8.2016
ppc64 keyworded thanks to ernsteiswuerfel!