Added a missing check.

Now that Argument also has an int_value field, we need to check it when testing equality of Argument objects.
Support integer macros, e.g. TCPS_CLOSED.

When a field is assigned a value defined by a macro, try to find that macro name rather than using the integer value (e.g. tp->t_state = TCPS_CLOSED rather than tp->t_state = 0x0).