Partially revert "src: remove unnecessary castings"
Partially revert "src: remove unnecessary castings"

This partially reverts commit 6e8573c9f62fc9db99c120298d9539be27fe282e.

%lu in 32-bits arch is only 4 bytes. Thanks to Jan Engelhardt for
spotting this.

Distrotech/libnetfilter_acct,Distrotech/libnetfilter_acct