makeWrapper: add --set-default and --set-eval

After #31497 starter quoting all values, there arouse the need to left some
values evaluated.

`--set-default var value` expands to `export var=${var-value}`, where value is
not evaluated and literally assigned to var unless it is already set.

`--set-eval var value` expands to `export var=$(eval echo value)`, where value
is evaluated by `eval`.