Hmm, this isn't used either.

src/include/regex/regexp.h

-/*
- * Copyright (c) 1986 by University of Toronto.
- * Copyright (c) 1989, 1993
- *		The Regents of the University of California.  All rights reserved.
- *
- * This code is derived from software contributed to Berkeley
- * by Henry Spencer.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *	  notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *	  notice, this list of conditions and the following disclaimer in the
- *	  documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *	  must display the following acknowledgement:
- *		This product includes software developed by the University of
- *		California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *	  may be used to endorse or promote products derived from this software
- *	  without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *		@(#)regexp.h	8.1 (Berkeley) 6/2/93
- */
-
-#ifndef _REGEXP_H_
-#define _REGEXP_H_
-
-/*
- * Definitions etc. for regexp(3) routines.
- *
- * Caveat:	this is V8 regexp(3) [actually, a reimplementation thereof],
- * not the System V one.
- */
-#define NSUBEXP  10
-typedef struct regexp
-{
-	char	   *startp[NSUBEXP];
-	char	   *endp[NSUBEXP];
-	char		regstart;		/* Internal use only. */
-	char		reganch;		/* Internal use only. */
-	char	   *regmust;		/* Internal use only. */
-	int			regmlen;		/* Internal use only. */
-	char		program[1];		/* Unwarranted chumminess with compiler. */
-}			regexp;
-
-/* since not all systems have cdefs.h, we'll use our own here - jolly */
-
-__BEGIN_DECLS
-regexp * pg95_regcomp __P((const char *));
-int pg95_regexec __P((const regexp *, const char *));
-void pg95_regsub __P((const regexp *, const char *, char *));
-void pg95_regerror __P((const char *));
-
-__END_DECLS
-
-#endif	 /* !_REGEXP_H_ */