Set the recursion limit.
Used for infinite loop check. If the value is -1, do not
check for infinite loops. Anyone who wants to enable that
check should change the value of this variable to be the
level of recursion that they want to check. Be careful setting
this variable, if the number is too low, it may report an
infinite loop situation, when there is none.
Post version 1.0.0, we'll make this a runtime feature.