diff --git a/contrib/nvi/regex/regex.h b/contrib/nvi/regex/regex.h
index 20ea7865c0a0..7d788514a54c 100644
--- a/contrib/nvi/regex/regex.h
+++ b/contrib/nvi/regex/regex.h
@@ -1,105 +1,115 @@
 /*	$NetBSD: regex.h,v 1.1.1.2 2008/05/18 14:31:38 aymeric Exp $ */
 
 /*-
  * Copyright (c) 1992 Henry Spencer.
  * Copyright (c) 1992, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Henry Spencer of the University of Toronto.
  *
  * 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. 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.
  *
  *	@(#)regex.h	8.1 (Berkeley) 6/2/93
  */
 
 #ifndef _REGEX_H_
 #define	_REGEX_H_
 
 #ifdef __REGEX_PRIVATE
 #include "config.h"
 #include "../common/multibyte.h"
 #endif
 
 /* types */
 typedef off_t regoff_t;
 
 typedef struct {
 	int re_magic;
 	size_t re_nsub;		/* number of parenthesized subexpressions */
 	const RCHAR_T *re_endp;	/* end pointer for REG_PEND */
 	struct re_guts *re_g;	/* none of your business :-) */
 } regex_t;
 
 typedef struct {
 	regoff_t rm_so;		/* start of match */
 	regoff_t rm_eo;		/* end of match */
 } regmatch_t;
 
 /* regcomp() flags */
 #define	REG_BASIC	0000
 #define	REG_EXTENDED	0001
 #define	REG_ICASE	0002
 #define	REG_NOSUB	0004
 #define	REG_NEWLINE	0010
 #define	REG_NOSPEC	0020
 #define	REG_PEND	0040
 #define	REG_DUMP	0200
 
 /* regerror() flags */
 #define	REG_NOMATCH	 1
 #define	REG_BADPAT	 2
 #define	REG_ECOLLATE	 3
 #define	REG_ECTYPE	 4
 #define	REG_EESCAPE	 5
 #define	REG_ESUBREG	 6
 #define	REG_EBRACK	 7
 #define	REG_EPAREN	 8
 #define	REG_EBRACE	 9
 #define	REG_BADBR	10
 #define	REG_ERANGE	11
 #define	REG_ESPACE	12
 #define	REG_BADRPT	13
 #define	REG_EMPTY	14
 #define	REG_ASSERT	15
 #define	REG_INVARG	16
 #define	REG_ATOI	255	/* convert name to number (!) */
 #define	REG_ITOA	0400	/* convert number to name (!) */
 
 /* regexec() flags */
 #define	REG_NOTBOL	00001
 #define	REG_NOTEOL	00002
 #define	REG_STARTEND	00004
 #define	REG_TRACE	00400	/* tracing of execution */
 #define	REG_LARGE	01000	/* force large representation */
 #define	REG_BACKR	02000	/* force use of backref code */
 
+#ifdef USE_WIDECHAR
+/*
+ * Avoid function name conflicts with the system regex functions.
+ * This is needed e.g. to build with AddressSanitizer.
+ */
+#define regcomp nvi_regcomp
+#define regerror nvi_regerror
+#define regexec nvi_regexec
+#define regfree nvi_regfree
+#endif
 int	regcomp(regex_t *, const RCHAR_T *, int);
 size_t	regerror(int, const regex_t *, char *, size_t);
 int	regexec(const regex_t *,
 	    const RCHAR_T *, size_t, regmatch_t [], int);
 void	regfree(regex_t *);
 
 #endif /* !_REGEX_H_ */