Prefixing a variable assignment with the
override keyword prevents that
variable's value from ever being changed again, except by way of another
override statement. This is functionality that Starlark doesn't support.
It can be removed by checking if the variable is defined before reassigning it. For example, replace:
override MY_VAR := foo MY_VAR := bar # MY_VAR is foo here
MY_VAR := foo # Generally this would be in a separate file that is included ifndef MY_VAR MY_VAR := bar enddef # MY_VAR is foo here