CoreLibs/object and CoreLibs/strict don't seem to get along

If you try to use both of those in a Lua file you get the following runtime error:

CoreLibs/object.lua:73: assign to undeclared variable 'mt'
stack traceback:
	[C]: in function 'error'
	CoreLibs/strict.lua:27: in metamethod 'newindex'
	CoreLibs/object.lua:73: in field 'extends'
	main.lua:34: in main chunk

duplicate of