Global problem with build ports on one architecture for another architecture, for example: x86 32-bit software for 64-bit system( such wine/doom etc.) building package for ARMV6/7 on x86/x86-64 system etc.
Use poudriere to do that.
(In reply to Mathieu Arnold from comment #1) Poudriere is interesting tool but: 1)Poudriere itself cannot use for creating 32-bit packages for 64-bit systems (not ordinary package 32-bit for 32-bit system) 2)I think for ordinary user doubtfully start install and setting up poudriere for just update few ports. Even if I add all depends for build 32-bit packages for 64-bit systems for example in doom port or create separated port (what making difficult ports structure) I still need 32-bit environment for build this package, posible use simular hack which used in i386-wine* but is this "too hacky way".
If poudriere is missing a few features, please, open bug reports there :-)