local args={...}
local kernel=args[1]
kernel._G=_G
kernel._U=setmetatable({},{
    __index = kernel._G,
    __newindex = function(t,k,v)
        if kernel.config.allowGlobalOverwrites or kernel.allowGlobalOverwrites then
            rawset(t,k,v)
            return
        end
        error("Attempt to modify global variable '"..k.."'",2)
    end,
    __metatable = false
})
kernel.allowGlobalOverwrites=true
kernel._U._G=kernel._U
kernel.allowGlobalOverwrites=false