there's some old pictures of my area's early settlers smoking meat hung on mesquite brush with wagon tarps thrown over it all.
point is ... a smokehouse is a vessel to contain smoke and heat(or not as in cold smoking).
so, yeah, aside from treated lumber (which used to have arsnic) any structure will do.
I've seen old outhouses ( moved to a better location
), chicken coops, well houses and small barns, up to custom walk-in brick buildings used to smoke meats, and other foods.