A Modest Extension to the C Preprocessor

[Doug Gwyn <gwyn>]

#ifndef	FOO_H_INCLUDED
#define	FOO_H_INCLUDED

	/* contents of "foo.h" */

#endif	FOO_H_INCLUDED

is an excellent solution to the "problem", if it be one, that
does not penalize those that had no problem with this business
in the first place.  This also solves the problem of making sure
that prerequisite files such as <sys/types.h> are included:

#ifndef	SYSTYPES_H_INCLUDED
#include	<sys/types.h>
#endif

	/* stuff that uses <sys/types.h> typedefs */

Good work, Dave!  I would, however, suggest shortening the
tag symbols a bit; probably "_H" could be safely removed.