1 This example has a function call in foo.c named "foo" that takes a forward
2 declaration to "struct bar" and uses it as a pointer argument. In main.c
3 we have a real declaration for "struct bar". We want to be able to find the
4 real definition of "struct bar" when we are stopped in foo in foo.c such that
5 when we stop in "foo" we see the contents of the "bar_ptr".