net/pkt-gen: fix on 32 bit platforms (again)

Exorcise -Werror for the third time.
Re-add patches needed to build on 32 bit platforms.
Please don't remove patches without understanding them first.

Fixes: 9305cd3f9321bfba95479b2b2a15c7639a790383
PR: 270440
See also: PR 264561, 230623
Approved by: portmgr (build fix blanket)