add unpack compat for good measure

snippet_safe_override.lua

@@ -4,6 +4,7 @@ _G.whosit = whosit
 
 -- provide table.pack if luajit is built without LUA52COMPAT
 local pack = table.pack or function(...) return {n = select("#", ...), ...} end
+local unpack = unpack or table.unpack
 
 -- use efficient deque or implement our own FIFO type of thing
 local formspec_log = futil and futil.Deque and futil.Deque()