discuss, since I think I'm the only one who has ever run this
or probably ever will.
Still far from perfect, of course. It's just an auxiliary tool that
whose output needs human interpretation.
But basically ...
see whether a public header will compile stand-alone.
recommend ISC_MAGIC_VALID where appropriate.
use "print" consistent throughout, instead of print/warn.
ignore a couple of special files.
fixed some conditions that caused premature termination of checking
595babf627