rust backend: fixing `with extern`
rust backend: fixing `with extern`

pombredanne/Rusthon,kustomzone/Rusthon,kustomzone/Rusthon,secureosv/pythia,secureosv/pythia,tempbottle/Rusthon,kustomzone/Rusthon,rootfs/Rusthon,tempbottle/Rusthon,secureosv/pythia,kustomzone/Rusthon,rootfs/Rusthon,pombredanne/Rusthon,pombredanne/Rusthon,tempbottle/Rusthon,kustomzone/Rusthon,rusthon/Rusthon,rootfs/Rusthon,secureosv/pythia,rusthon/Rusthon,rootfs/Rusthon,rusthon/Rusthon,pombredanne/Rusthon,secureosv/pythia,pombredanne/Rusthon,rusthon/Rusthon,rusthon/Rusthon,tempbottle/Rusthon,tempbottle/Rusthon,rootfs/Rusthon