Fix build against poppler 22.08

Jeremy Bícharequested to merge
jbicha/dia:poppler2208 into debian/master

Unfortunately, this build fix only works against new poppler and it will fail to build with poppler 22.02 currently in Unstable.

Would you like us to NMU this when we start the poppler 22.08 transition?

Closes: https://bugs.debian.org/1017025 LP: #1980402

Merge request reports