diff --git a/ext/ereg/regex/cclass.h b/ext/ereg/regex/cclass.h
index 6227f810b72..df41694b040 100644
--- a/ext/ereg/regex/cclass.h
+++ b/ext/ereg/regex/cclass.h
@@ -1,8 +1,8 @@
 /* character-class table */
 static struct cclass {
-	char *name;
-	char *chars;
-	char *multis;
+	unsigned char *name;
+	unsigned char *chars;
+	unsigned char *multis;
 } cclasses[] = {
 	{"alnum",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",				""},
 	{"alpha",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
diff --git a/ext/ereg/regex/debug.c b/ext/ereg/regex/debug.c
index c0feaeb1694..3db93ef293a 100644
--- a/ext/ereg/regex/debug.c
+++ b/ext/ereg/regex/debug.c
@@ -124,9 +124,9 @@ FILE *d;
 			break;
 		case OCHAR:
 			if (strchr("\\|()^$.[+*?{}!<> ", (char)opnd) != NULL)
-				fprintf(d, "\\%c", (char)opnd);
+				fprintf(d, "\\%c", (unsigned char)opnd);
 			else
-				fprintf(d, "%s", regchar((char)opnd));
+				fprintf(d, "%s", regchar((unsigned char)opnd));
 			break;
 		case OBOL:
 			fprintf(d, "^");
@@ -228,11 +228,11 @@ FILE *d;
  - regchar - make a character printable
  == static char *regchar(int ch);
  */
-static char *			/* -> representation */
+static unsigned char *			/* -> representation */
 regchar(ch)
 int ch;
 {
-	static char buf[10];
+	static unsigned char buf[10];
 
 	if (isprint(ch) || ch == ' ')
 		sprintf(buf, "%c", ch);
diff --git a/ext/ereg/regex/engine.c b/ext/ereg/regex/engine.c
index 0b88dcf1ed8..c4bdc8079f0 100644
--- a/ext/ereg/regex/engine.c
+++ b/ext/ereg/regex/engine.c
@@ -33,11 +33,11 @@ struct match {
 	struct re_guts *g;
 	int eflags;
 	regmatch_t *pmatch;	/* [nsub+1] (0 element unused) */
-	char *offp;		/* offsets work from here */
-	char *beginp;		/* start of string -- virtual NUL precedes */
-	char *endp;		/* end of string -- virtual NUL here */
-	char *coldp;		/* can be no match starting before here */
-	char **lastpos;		/* [nplus+1] */
+	unsigned char *offp;		/* offsets work from here */
+	unsigned char *beginp;		/* start of string -- virtual NUL precedes */
+	unsigned char *endp;		/* end of string -- virtual NUL here */
+	unsigned char *coldp;		/* can be no match starting before here */
+	unsigned char **lastpos;		/* [nplus+1] */
 	STATEVARS;
 	states st;		/* current states */
 	states fresh;		/* states for a fresh start */
@@ -65,20 +65,20 @@ struct match {
 static int			/* 0 success, REG_NOMATCH failure */
 matcher(g, string, nmatch, pmatch, eflags)
 register struct re_guts *g;
-char *string;
+unsigned char *string;
 size_t nmatch;
 regmatch_t pmatch[];
 int eflags;
 {
-	register char *endp;
+	register unsigned char *endp;
 	register size_t i;
 	struct match mv;
 	register struct match *m = &mv;
-	register char *dp;
+	register unsigned char *dp;
 	const register sopno gf = g->firststate+1;	/* +1 for OEND */
 	const register sopno gl = g->laststate;
-	char *start;
-	char *stop;
+	unsigned char *start;
+	unsigned char *stop;
 
 	/* simplify the situation where possible */
 	if (g->cflags&REG_NOSUB)
@@ -156,10 +156,10 @@ int eflags;
 			dp = dissect(m, m->coldp, endp, gf, gl);
 		} else {
 			if (g->nplus > 0 && m->lastpos == NULL)
-				m->lastpos = (char **)malloc((g->nplus+1) *
-							sizeof(char *));
+				m->lastpos = (unsigned char **)malloc((g->nplus+1) *
+							sizeof(unsigned char *));
 			if (g->nplus > 0 && m->lastpos == NULL) {
-				free(m->pmatch);
+				free((char *)m->pmatch);
 				STATETEARDOWN(m);
 				return(REG_ESPACE);
 			}
@@ -225,30 +225,30 @@ int eflags;
 
 /*
  - dissect - figure out what matched what, no back references
- == static char *dissect(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *dissect(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* == stop (success) always */
+static unsigned char *			/* == stop (success) always */
 dissect(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register int i;
 	register sopno ss;	/* start sop of current subRE */
 	register sopno es;	/* end sop of current subRE */
-	register char *sp;	/* start of string matched by it */
-	register char *stp;	/* string matched by it cannot pass here */
-	register char *rest;	/* start of rest of string */
-	register char *tail;	/* string unmatched by rest of RE */
+	register unsigned char *sp;	/* start of string matched by it */
+	register unsigned char *stp;	/* string matched by it cannot pass here */
+	register unsigned char *rest;	/* start of rest of string */
+	register unsigned char *tail;	/* string unmatched by rest of RE */
 	register sopno ssub;	/* start sop of subsubRE */
 	register sopno esub;	/* end sop of subsubRE */
-	register char *ssp;	/* start of string matched by subsubRE */
-	register char *sep;	/* end of string matched by subsubRE */
-	register char *oldssp;	/* previous ssp */
-	register char *dp;
+	register unsigned char *ssp;	/* start of string matched by subsubRE */
+	register unsigned char *sep;	/* end of string matched by subsubRE */
+	register unsigned char *oldssp;	/* previous ssp */
+	register unsigned char *dp;
 
 	AT("diss", start, stop, startst, stopst);
 	sp = start;
@@ -413,25 +413,25 @@ sopno stopst;
 
 /*
  - backref - figure out what matched what, figuring in back references
- == static char *backref(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst, sopno lev);
+ == static unsigned char *backref(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst, sopno lev);
  */
-static char *			/* == stop (success) or NULL (failure) */
+static unsigned char *			/* == stop (success) or NULL (failure) */
 backref(m, start, stop, startst, stopst, lev)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 sopno lev;			/* PLUS nesting level */
 {
 	register int i;
 	register sopno ss;	/* start sop of current subRE */
-	register char *sp;	/* start of string matched by it */
+	register unsigned char *sp;	/* start of string matched by it */
 	register sopno ssub;	/* start sop of subsubRE */
 	register sopno esub;	/* end sop of subsubRE */
-	register char *ssp;	/* start of string matched by subsubRE */
-	register char *dp;
+	register unsigned char *ssp;	/* start of string matched by subsubRE */
+	register unsigned char *dp;
 	register size_t len;
 	register int hard;
 	register sop s;
@@ -446,7 +446,7 @@ sopno lev;			/* PLUS nesting level */
 	for (ss = startst; !hard && ss < stopst; ss++)
 		switch (OP(s = m->g->strip[ss])) {
 		case OCHAR:
-			if (sp == stop || *sp++ != (char)OPND(s))
+			if (sp == stop || *sp++ != (unsigned char)OPND(s))
 				return(NULL);
 			break;
 		case OANY:
@@ -613,31 +613,31 @@ sopno lev;			/* PLUS nesting level */
 	/* "can't happen" */
 	assert(nope);
 	/* NOTREACHED */
-	return((char *)NULL);	/* dummy */
+	return((unsigned char *)NULL);	/* dummy */
 }
 
 /*
  - fast - step through the string at top speed
- == static char *fast(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *fast(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* where tentative match ended, or NULL */
+static unsigned char *			/* where tentative match ended, or NULL */
 fast(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register states st = m->st;
 	register states fresh = m->fresh;
 	register states tmp = m->tmp;
-	register char *p = start;
+	register unsigned char *p = start;
 	register int c = (start == m->beginp) ? OUT : *(start-1);
 	register int lastc;	/* previous c */
 	register int flagch;
 	register int i;
-	register char *coldp;	/* last p after which no match was underway */
+	register unsigned char *coldp;	/* last p after which no match was underway */
 
 	CLEAR(st);
 	SET1(st, startst);
@@ -709,26 +709,26 @@ sopno stopst;
 
 /*
  - slow - step through the string more deliberately
- == static char *slow(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *slow(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* where it ended */
+static unsigned char *			/* where it ended */
 slow(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register states st = m->st;
 	register states empty = m->empty;
 	register states tmp = m->tmp;
-	register char *p = start;
+	register unsigned char *p = start;
 	register int c = (start == m->beginp) ? OUT : *(start-1);
 	register int lastc;	/* previous c */
 	register int flagch;
 	register int i;
-	register char *matchp;	/* last p at which a match ended */
+	register unsigned char *matchp;	/* last p at which a match ended */
 
 	AT("slow", start, stop, startst, stopst);
 	CLEAR(st);
@@ -805,8 +805,8 @@ sopno stopst;
  == #define	BOW	(BOL+4)
  == #define	EOW	(BOL+5)
  == #define	CODEMAX	(BOL+5)		// highest code used
- == #define	NONCHAR(c)	((c) > CHAR_MAX)
- == #define	NNONCHAR	(CODEMAX-CHAR_MAX)
+ == #define	NONCHAR(c)	((c) > UCHAR_MAX)
+ == #define	NNONCHAR	(CODEMAX-UCHAR_MAX)
  */
 static states
 step(g, start, stop, bef, ch, aft)
@@ -832,8 +832,8 @@ register states aft;		/* states already known reachable after */
 			break;
 		case OCHAR:
 			/* only characters can match */
-			assert(!NONCHAR(ch) || ch != (char)OPND(s));
-			if (ch == (char)OPND(s))
+			assert(!NONCHAR(ch) || ch != (unsigned char)OPND(s));
+			if (ch == (unsigned char)OPND(s))
 				FWD(aft, bef, 1);
 			break;
 		case OBOL:
@@ -926,14 +926,14 @@ register states aft;		/* states already known reachable after */
 /*
  - print - print a set of states
  == #ifdef REDEBUG
- == static void print(struct match *m, char *caption, states st, \
+ == static void print(struct match *m, unsigned char *caption, states st, \
  ==	int ch, FILE *d);
  == #endif
  */
 static void
 print(m, caption, st, ch, d)
 struct match *m;
-char *caption;
+unsigned char *caption;
 states st;
 int ch;
 FILE *d;
@@ -959,16 +959,16 @@ FILE *d;
 /* 
  - at - print current situation
  == #ifdef REDEBUG
- == static void at(struct match *m, char *title, char *start, char *stop, \
+ == static void at(struct match *m, unsigned char *title, unsigned char *start, unsigned char *stop, \
  ==						sopno startst, sopno stopst);
  == #endif
  */
 static void
 at(m, title, start, stop, startst, stopst)
 struct match *m;
-char *title;
-char *start;
-char *stop;
+unsigned char *title;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
@@ -985,7 +985,7 @@ sopno stopst;
 /*
  - pchar - make a character printable
  == #ifdef REDEBUG
- == static char *pchar(int ch);
+ == static unsigned char *pchar(int ch);
  == #endif
  *
  * Is this identical to regchar() over in debug.c?  Well, yes.  But a
@@ -993,11 +993,11 @@ sopno stopst;
  * a matching debug.o, and this is convenient.  It all disappears in
  * the non-debug compilation anyway, so it doesn't matter much.
  */
-static char *			/* -> representation */
+static unsigned char *			/* -> representation */
 pchar(ch)
 int ch;
 {
-	static char pbuf[10];
+	static unsigned char pbuf[10];
 
 	if (isprint(ch) || ch == ' ')
 		sprintf(pbuf, "%c", ch);
diff --git a/ext/ereg/regex/engine.ih b/ext/ereg/regex/engine.ih
index cc98334e752..9a301838bcd 100644
--- a/ext/ereg/regex/engine.ih
+++ b/ext/ereg/regex/engine.ih
@@ -4,11 +4,11 @@ extern "C" {
 #endif
 
 /* === engine.c === */
-static int matcher(register struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
-static char *dissect(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
-static char *backref(register struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev);
-static char *fast(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
-static char *slow(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
+static int matcher(register struct re_guts *g, unsigned char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
+static unsigned char *dissect(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
+static unsigned char *backref(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst, sopno lev);
+static unsigned char *fast(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
+static unsigned char *slow(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
 static states step(register struct re_guts *g, sopno start, sopno stop, register states bef, int ch, register states aft);
 #define	BOL	(OUT+1)
 #define	EOL	(BOL+1)
@@ -17,16 +17,16 @@ static states step(register struct re_guts *g, sopno start, sopno stop, register
 #define	BOW	(BOL+4)
 #define	EOW	(BOL+5)
 #define	CODEMAX	(BOL+5)		/* highest code used */
-#define	NONCHAR(c)	((c) > CHAR_MAX)
-#define	NNONCHAR	(CODEMAX-CHAR_MAX)
+#define	NONCHAR(c)	((c) > UCHAR_MAX)
+#define	NNONCHAR	(CODEMAX-UCHAR_MAX)
 #ifdef REDEBUG
-static void print(struct match *m, char *caption, states st, int ch, FILE *d);
+static void print(struct match *m, unsigned char *caption, states st, int ch, FILE *d);
 #endif
 #ifdef REDEBUG
-static void at(struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst);
+static void at(struct match *m, unsigned char *title, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
 #endif
 #ifdef REDEBUG
-static char *pchar(int ch);
+static unsigned char *pchar(int ch);
 #endif
 
 #ifdef __cplusplus
diff --git a/ext/ereg/regex/regcomp.c b/ext/ereg/regex/regcomp.c
index 0b939461bd7..ec034d4c4ce 100644
--- a/ext/ereg/regex/regcomp.c
+++ b/ext/ereg/regex/regcomp.c
@@ -19,8 +19,8 @@
  * other clumsinesses
  */
 struct parse {
-	char *next;		/* next character in RE */
-	char *end;		/* end of string (-> NUL normally) */
+	unsigned char *next;		/* next character in RE */
+	unsigned char *end;		/* end of string (-> NUL normally) */
 	int error;		/* has an error been seen? */
 	sop *strip;		/* malloced strip */
 	sopno ssize;		/* malloced strip size (allocated) */
@@ -34,7 +34,7 @@ struct parse {
 
 #include "regcomp.ih"
 
-static char nuls[10];		/* place to point scanner in event of error */
+static unsigned char nuls[10];		/* place to point scanner in event of error */
 
 /*
  * macros for use with parse structure
@@ -127,7 +127,7 @@ int cflags;
 
 	/* set things up */
 	p->g = g;
-	p->next = (char *)pattern;	/* convenience; we do not modify it */
+	p->next = (unsigned char *)pattern;	/* convenience; we do not modify it */
 	p->end = p->next + len;
 	p->error = 0;
 	p->ncsalloc = 0;
@@ -147,7 +147,7 @@ int cflags;
 	g->mlen = 0;
 	g->nsub = 0;
 	g->ncategories = 1;	/* category 0 is "everything else" */
-	g->categories = &g->catspace[-(CHAR_MIN)];
+	g->categories = &g->catspace[0];
 	(void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
 	g->backrefs = 0;
 
@@ -193,7 +193,7 @@ p_ere(p, stop)
 register struct parse *p;
 int stop;			/* character this ERE should end at */
 {
-	register char c;
+	register unsigned char c;
 	register sopno prevback = 0;
 	register sopno prevfwd = 0;
 	register sopno conc;
@@ -238,7 +238,7 @@ static void
 p_ere_exp(p)
 register struct parse *p;
 {
-	register char c;
+	register unsigned char c;
 	register sopno pos;
 	register int count;
 	register int count2;
@@ -518,7 +518,7 @@ int starordinary;		/* is a leading * an ordinary character? */
 		REQUIRE(starordinary, REG_BADRPT);
 		/* FALLTHROUGH */
 	default:
-		ordinary(p, (char)c);	/* takes off BACKSL, if any */
+		ordinary(p, (unsigned char)c);	/* takes off BACKSL, if any */
 		break;
 	}
 
@@ -657,8 +657,8 @@ p_b_term(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char c;
-	register char start, finish;
+	register unsigned char c;
+	register unsigned char start, finish;
 	register int i;
 
 	/* classify what we've got */
@@ -723,11 +723,11 @@ p_b_cclass(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char *sp = p->next;
+	register unsigned char *sp = p->next;
 	register struct cclass *cp;
 	register size_t len;
-	register char *u;
-	register char c;
+	register unsigned char *u;
+	register unsigned char c;
 
 	while (MORE() && isalpha(PEEK()))
 		NEXT();
@@ -759,7 +759,7 @@ p_b_eclass(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char c;
+	register unsigned char c;
 
 	c = p_b_coll_elem(p, '=');
 	CHadd(cs, c);
@@ -769,11 +769,11 @@ register cset *cs;
  - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
  == static char p_b_symbol(register struct parse *p);
  */
-static char			/* value of symbol */
+static unsigned char			/* value of symbol */
 p_b_symbol(p)
 register struct parse *p;
 {
-	register char value;
+	register unsigned char value;
 
 	REQUIRE(MORE(), REG_EBRACK);
 	if (!EATTWO('[', '.'))
@@ -789,12 +789,12 @@ register struct parse *p;
  - p_b_coll_elem - parse a collating-element name and look it up
  == static char p_b_coll_elem(register struct parse *p, int endc);
  */
-static char			/* value of collating element */
+static unsigned char			/* value of collating element */
 p_b_coll_elem(p, endc)
 register struct parse *p;
 int endc;			/* name ended by endc,']' */
 {
-	register char *sp = p->next;
+	register unsigned char *sp = p->next;
 	register struct cname *cp;
 	register int len;
 
@@ -818,7 +818,7 @@ int endc;			/* name ended by endc,']' */
  - othercase - return the case counterpart of an alphabetic
  == static char othercase(int ch);
  */
-static char			/* if no counterpart, return ch */
+static unsigned char			/* if no counterpart, return ch */
 othercase(ch)
 int ch;
 {
@@ -842,9 +842,9 @@ bothcases(p, ch)
 register struct parse *p;
 int ch;
 {
-	register char *oldnext = p->next;
-	register char *oldend = p->end;
-	char bracket[3];
+	register unsigned char *oldnext = p->next;
+	register unsigned char *oldend = p->end;
+	unsigned char bracket[3];
 
 	assert(othercase(ch) != ch);	/* p_bracket() would recurse */
 	p->next = bracket;
@@ -888,9 +888,9 @@ static void
 nonnewline(p)
 register struct parse *p;
 {
-	register char *oldnext = p->next;
-	register char *oldend = p->end;
-	char bracket[4];
+	register unsigned char *oldnext = p->next;
+	register unsigned char *oldend = p->end;
+	unsigned char bracket[4];
 
 	p->next = bracket;
 	p->end = bracket+3;
@@ -1015,19 +1015,19 @@ register struct parse *p;
 		if (p->g->sets == NULL)
 			p->g->sets = (cset *)malloc(nc * sizeof(cset));
 		else
-			p->g->sets = (cset *)realloc((char *)p->g->sets,
+			p->g->sets = (cset *)realloc((unsigned char *)p->g->sets,
 							nc * sizeof(cset));
 		if (p->g->setbits == NULL)
 			p->g->setbits = (uch *)malloc(nbytes);
 		else {
-			p->g->setbits = (uch *)realloc((char *)p->g->setbits,
+			p->g->setbits = (uch *)realloc((unsigned char *)p->g->setbits,
 								nbytes);
 			/* xxx this isn't right if setbits is now NULL */
 			for (i = 0; i < no; i++)
 				p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT);
 		}
 		if (p->g->sets != NULL && p->g->setbits != NULL)
-			(void) memset((char *)p->g->setbits + (nbytes - css),
+			(void) memset((unsigned char *)p->g->setbits + (nbytes - css),
 								0, css);
 		else {
 			no = 0;
@@ -1120,7 +1120,7 @@ register cset *cs;
 
 	for (i = 0; i < css; i++)
 		if (CHIN(cs, i))
-			return((char)i);
+			return((unsigned char)i);
 	assert(never);
 	return(0);		/* arbitrary */
 }
@@ -1153,7 +1153,7 @@ static void
 mcadd(p, cs, cp)
 register struct parse *p;
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
 	register size_t oldend = cs->smultis;
 
@@ -1174,14 +1174,14 @@ register char *cp;
 #if 0
 /*
  - mcsub - subtract a collating element from a cset
- == static void mcsub(register cset *cs, register char *cp);
+ == static void mcsub(register cset *cs, register unsigned char *cp);
  */
 static void
 mcsub(cs, cp)
-register cset *cs;
-register char *cp;
+register unsigned cset *cs;
+register unsigned char *cp;
 {
-	register char *fp = mcfind(cs, cp);
+	register unsigned char *fp = mcfind(cs, cp);
 	register size_t len = strlen(fp);
 
 	assert(fp != NULL);
@@ -1201,12 +1201,12 @@ register char *cp;
 
 /*
  - mcin - is a collating element in a cset?
- == static int mcin(register cset *cs, register char *cp);
+ == static int mcin(register cset *cs, register unsigned char *cp);
  */
 static int
 mcin(cs, cp)
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
 	return(mcfind(cs, cp) != NULL);
 }
@@ -1214,14 +1214,14 @@ register char *cp;
 
 /*
  - mcfind - find a collating element in a cset
- == static char *mcfind(register cset *cs, register char *cp);
+ == static unsigned char *mcfind(register cset *cs, register unsigned char *cp);
  */
-static char *
+static unsigned char *
 mcfind(cs, cp)
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
-	register char *p;
+	register unsigned char *p;
 
 	if (cs->multis == NULL)
 		return(NULL);
@@ -1322,11 +1322,11 @@ register struct re_guts *g;
 	if (p->error != 0)
 		return;
 
-	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
+	for (c = 0; c <= UCHAR_MAX; c++)
 		if (cats[c] == 0 && isinsets(g, c)) {
 			cat = g->ncategories++;
 			cats[c] = cat;
-			for (c2 = c+1; c2 <= CHAR_MAX; c2++)
+			for (c2 = c+1; c2 <= UCHAR_MAX; c2++)
 				if (cats[c2] == 0 && samesets(g, c, c2))
 					cats[c2] = cat;
 		}
@@ -1477,7 +1477,7 @@ register struct parse *p;
 register struct re_guts *g;
 {
 	g->nstates = p->slen;
-	g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
+	g->strip = (sop *)realloc((unsigned char *)p->strip, p->slen * sizeof(sop));
 	if (g->strip == NULL) {
 		SETERROR(REG_ESPACE);
 		g->strip = p->strip;
@@ -1504,7 +1504,7 @@ register struct re_guts *g;
 	register sop *newstart = NULL;
 	register sopno newlen;
 	register sop s;
-	register char *cp;
+	register unsigned char *cp;
 	register sopno i;
 
 	/* avoid making error situations worse */
@@ -1565,7 +1565,7 @@ register struct re_guts *g;
 		while (OP(s = *scan++) != OCHAR)
 			continue;
 		assert(cp < g->must + g->mlen);
-		*cp++ = (char)OPND(s);
+		*cp++ = (unsigned char)OPND(s);
 	}
 	assert(cp == g->must + g->mlen);
 	*cp++ = '\0';		/* just on general principles */
diff --git a/ext/ereg/regex/regcomp.ih b/ext/ereg/regex/regcomp.ih
index 6efafebf602..c93d32e51d3 100644
--- a/ext/ereg/regex/regcomp.ih
+++ b/ext/ereg/regex/regcomp.ih
@@ -14,9 +14,9 @@ static void p_bracket(register struct parse *p);
 static void p_b_term(register struct parse *p, register cset *cs);
 static void p_b_cclass(register struct parse *p, register cset *cs);
 static void p_b_eclass(register struct parse *p, register cset *cs);
-static char p_b_symbol(register struct parse *p);
-static char p_b_coll_elem(register struct parse *p, int endc);
-static char othercase(int ch);
+static unsigned char p_b_symbol(register struct parse *p);
+static unsigned char p_b_coll_elem(register struct parse *p, int endc);
+static unsigned char othercase(int ch);
 static void bothcases(register struct parse *p, int ch);
 static void ordinary(register struct parse *p, register int ch);
 static void nonnewline(register struct parse *p);
@@ -27,11 +27,11 @@ static void freeset(register struct parse *p, register cset *cs);
 static int freezeset(register struct parse *p, register cset *cs);
 static int firstch(register struct parse *p, register cset *cs);
 static int nch(register struct parse *p, register cset *cs);
-static void mcadd(register struct parse *p, register cset *cs, register char *cp);
+static void mcadd(register struct parse *p, register cset *cs, register unsigned char *cp);
 #if 0
-static void mcsub(register cset *cs, register char *cp);
-static int mcin(register cset *cs, register char *cp);
-static char *mcfind(register cset *cs, register char *cp);
+static void mcsub(register cset *cs, register unsigned char *cp);
+static int mcin(register cset *cs, register unsigned char *cp);
+static unsigned char *mcfind(register cset *cs, register unsigned char *cp);
 #endif
 static void mcinvert(register struct parse *p, register cset *cs);
 static void mccase(register struct parse *p, register cset *cs);
diff --git a/ext/ereg/regex/regex2.h b/ext/ereg/regex/regex2.h
index 7cd39a59ae5..4996f96ecd3 100644
--- a/ext/ereg/regex/regex2.h
+++ b/ext/ereg/regex/regex2.h
@@ -10,7 +10,7 @@
  = typedef struct {
  = 	int re_magic;
  = 	size_t re_nsub;		// number of parenthesized subexpressions
- = 	const char *re_endp;	// end pointer for REG_PEND
+ = 	const unsigned char *re_endp;	// end pointer for REG_PEND
  = 	struct re_guts *re_g;	// none of your business :-)
  = } regex_t;
  = typedef struct {
@@ -90,7 +90,7 @@ typedef struct {
 	uch mask;		/* bit within array */
 	uch hash;		/* hash code */
 	size_t smultis;
-	char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
+	unsigned char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
 } cset;
 /* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
 #define	CHadd(cs, c)	((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
@@ -125,8 +125,8 @@ struct re_guts {
 	int nbol;		/* number of ^ used */
 	int neol;		/* number of $ used */
 	int ncategories;	/* how many character categories */
-	cat_t *categories;	/* ->catspace[-CHAR_MIN] */
-	char *must;		/* match must contain this string */
+	cat_t *categories;	/* ->catspace[-UCHAR_MIN] */
+	unsigned char *must;		/* match must contain this string */
 	int mlen;		/* length of must */
 	size_t nsub;		/* copy of re_nsub */
 	int backrefs;		/* does it use back references? */
@@ -136,5 +136,5 @@ struct re_guts {
 };
 
 /* misc utilities */
-#define	OUT	(CHAR_MAX+1)	/* a non-character value */
+#define	OUT	(UCHAR_MAX+1)	/* a non-character value */
 #define	ISWORD(c)	(isalnum(c) || (c) == '_')
diff --git a/ext/ereg/regex/regexec.c b/ext/ereg/regex/regexec.c
index 7888d02368c..c8cb8fdf564 100644
--- a/ext/ereg/regex/regexec.c
+++ b/ext/ereg/regex/regexec.c
@@ -67,14 +67,14 @@ static int nope = 0;		/* for use in asserts; shuts lint up */
 #undef	SNAMES
 
 /* macros for manipulating states, large version */
-#define	states	char *
+#define	states	unsigned char *
 #define	CLEAR(v)	memset(v, 0, m->g->nstates)
 #define	SET0(v, n)	((v)[n] = 0)
 #define	SET1(v, n)	((v)[n] = 1)
 #define	ISSET(v, n)	((v)[n])
 #define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
 #define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
-#define	STATEVARS	int vn; char *space
+#define	STATEVARS	int vn; unsigned char *space
 #define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
 				if ((m)->space == NULL) return(REG_ESPACE); \
 				(m)->vn = 0; }
@@ -132,7 +132,7 @@ int eflags;
 	eflags = GOODFLAGS(eflags);
 
 	if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
-		return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
+		return(smatcher(g, (unsigned char *)string, nmatch, pmatch, eflags));
 	else
-		return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
+		return(lmatcher(g, (unsigned char *)string, nmatch, pmatch, eflags));
 }
diff --git a/regex/cclass.h b/regex/cclass.h
index 6227f810b72..df41694b040 100644
--- a/regex/cclass.h
+++ b/regex/cclass.h
@@ -1,8 +1,8 @@
 /* character-class table */
 static struct cclass {
-	char *name;
-	char *chars;
-	char *multis;
+	unsigned char *name;
+	unsigned char *chars;
+	unsigned char *multis;
 } cclasses[] = {
 	{"alnum",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",				""},
 	{"alpha",	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
diff --git a/regex/debug.c b/regex/debug.c
index c0feaeb1694..3db93ef293a 100644
--- a/regex/debug.c
+++ b/regex/debug.c
@@ -124,9 +124,9 @@ FILE *d;
 			break;
 		case OCHAR:
 			if (strchr("\\|()^$.[+*?{}!<> ", (char)opnd) != NULL)
-				fprintf(d, "\\%c", (char)opnd);
+				fprintf(d, "\\%c", (unsigned char)opnd);
 			else
-				fprintf(d, "%s", regchar((char)opnd));
+				fprintf(d, "%s", regchar((unsigned char)opnd));
 			break;
 		case OBOL:
 			fprintf(d, "^");
@@ -228,11 +228,11 @@ FILE *d;
  - regchar - make a character printable
  == static char *regchar(int ch);
  */
-static char *			/* -> representation */
+static unsigned char *			/* -> representation */
 regchar(ch)
 int ch;
 {
-	static char buf[10];
+	static unsigned char buf[10];
 
 	if (isprint(ch) || ch == ' ')
 		sprintf(buf, "%c", ch);
diff --git a/regex/engine.c b/regex/engine.c
index 0b88dcf1ed8..c4bdc8079f0 100644
--- a/regex/engine.c
+++ b/regex/engine.c
@@ -33,11 +33,11 @@ struct match {
 	struct re_guts *g;
 	int eflags;
 	regmatch_t *pmatch;	/* [nsub+1] (0 element unused) */
-	char *offp;		/* offsets work from here */
-	char *beginp;		/* start of string -- virtual NUL precedes */
-	char *endp;		/* end of string -- virtual NUL here */
-	char *coldp;		/* can be no match starting before here */
-	char **lastpos;		/* [nplus+1] */
+	unsigned char *offp;		/* offsets work from here */
+	unsigned char *beginp;		/* start of string -- virtual NUL precedes */
+	unsigned char *endp;		/* end of string -- virtual NUL here */
+	unsigned char *coldp;		/* can be no match starting before here */
+	unsigned char **lastpos;		/* [nplus+1] */
 	STATEVARS;
 	states st;		/* current states */
 	states fresh;		/* states for a fresh start */
@@ -65,20 +65,20 @@ struct match {
 static int			/* 0 success, REG_NOMATCH failure */
 matcher(g, string, nmatch, pmatch, eflags)
 register struct re_guts *g;
-char *string;
+unsigned char *string;
 size_t nmatch;
 regmatch_t pmatch[];
 int eflags;
 {
-	register char *endp;
+	register unsigned char *endp;
 	register size_t i;
 	struct match mv;
 	register struct match *m = &mv;
-	register char *dp;
+	register unsigned char *dp;
 	const register sopno gf = g->firststate+1;	/* +1 for OEND */
 	const register sopno gl = g->laststate;
-	char *start;
-	char *stop;
+	unsigned char *start;
+	unsigned char *stop;
 
 	/* simplify the situation where possible */
 	if (g->cflags&REG_NOSUB)
@@ -156,10 +156,10 @@ int eflags;
 			dp = dissect(m, m->coldp, endp, gf, gl);
 		} else {
 			if (g->nplus > 0 && m->lastpos == NULL)
-				m->lastpos = (char **)malloc((g->nplus+1) *
-							sizeof(char *));
+				m->lastpos = (unsigned char **)malloc((g->nplus+1) *
+							sizeof(unsigned char *));
 			if (g->nplus > 0 && m->lastpos == NULL) {
-				free(m->pmatch);
+				free((char *)m->pmatch);
 				STATETEARDOWN(m);
 				return(REG_ESPACE);
 			}
@@ -225,30 +225,30 @@ int eflags;
 
 /*
  - dissect - figure out what matched what, no back references
- == static char *dissect(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *dissect(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* == stop (success) always */
+static unsigned char *			/* == stop (success) always */
 dissect(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register int i;
 	register sopno ss;	/* start sop of current subRE */
 	register sopno es;	/* end sop of current subRE */
-	register char *sp;	/* start of string matched by it */
-	register char *stp;	/* string matched by it cannot pass here */
-	register char *rest;	/* start of rest of string */
-	register char *tail;	/* string unmatched by rest of RE */
+	register unsigned char *sp;	/* start of string matched by it */
+	register unsigned char *stp;	/* string matched by it cannot pass here */
+	register unsigned char *rest;	/* start of rest of string */
+	register unsigned char *tail;	/* string unmatched by rest of RE */
 	register sopno ssub;	/* start sop of subsubRE */
 	register sopno esub;	/* end sop of subsubRE */
-	register char *ssp;	/* start of string matched by subsubRE */
-	register char *sep;	/* end of string matched by subsubRE */
-	register char *oldssp;	/* previous ssp */
-	register char *dp;
+	register unsigned char *ssp;	/* start of string matched by subsubRE */
+	register unsigned char *sep;	/* end of string matched by subsubRE */
+	register unsigned char *oldssp;	/* previous ssp */
+	register unsigned char *dp;
 
 	AT("diss", start, stop, startst, stopst);
 	sp = start;
@@ -413,25 +413,25 @@ sopno stopst;
 
 /*
  - backref - figure out what matched what, figuring in back references
- == static char *backref(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst, sopno lev);
+ == static unsigned char *backref(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst, sopno lev);
  */
-static char *			/* == stop (success) or NULL (failure) */
+static unsigned char *			/* == stop (success) or NULL (failure) */
 backref(m, start, stop, startst, stopst, lev)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 sopno lev;			/* PLUS nesting level */
 {
 	register int i;
 	register sopno ss;	/* start sop of current subRE */
-	register char *sp;	/* start of string matched by it */
+	register unsigned char *sp;	/* start of string matched by it */
 	register sopno ssub;	/* start sop of subsubRE */
 	register sopno esub;	/* end sop of subsubRE */
-	register char *ssp;	/* start of string matched by subsubRE */
-	register char *dp;
+	register unsigned char *ssp;	/* start of string matched by subsubRE */
+	register unsigned char *dp;
 	register size_t len;
 	register int hard;
 	register sop s;
@@ -446,7 +446,7 @@ sopno lev;			/* PLUS nesting level */
 	for (ss = startst; !hard && ss < stopst; ss++)
 		switch (OP(s = m->g->strip[ss])) {
 		case OCHAR:
-			if (sp == stop || *sp++ != (char)OPND(s))
+			if (sp == stop || *sp++ != (unsigned char)OPND(s))
 				return(NULL);
 			break;
 		case OANY:
@@ -613,31 +613,31 @@ sopno lev;			/* PLUS nesting level */
 	/* "can't happen" */
 	assert(nope);
 	/* NOTREACHED */
-	return((char *)NULL);	/* dummy */
+	return((unsigned char *)NULL);	/* dummy */
 }
 
 /*
  - fast - step through the string at top speed
- == static char *fast(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *fast(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* where tentative match ended, or NULL */
+static unsigned char *			/* where tentative match ended, or NULL */
 fast(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register states st = m->st;
 	register states fresh = m->fresh;
 	register states tmp = m->tmp;
-	register char *p = start;
+	register unsigned char *p = start;
 	register int c = (start == m->beginp) ? OUT : *(start-1);
 	register int lastc;	/* previous c */
 	register int flagch;
 	register int i;
-	register char *coldp;	/* last p after which no match was underway */
+	register unsigned char *coldp;	/* last p after which no match was underway */
 
 	CLEAR(st);
 	SET1(st, startst);
@@ -709,26 +709,26 @@ sopno stopst;
 
 /*
  - slow - step through the string more deliberately
- == static char *slow(register struct match *m, char *start, \
- ==	char *stop, sopno startst, sopno stopst);
+ == static unsigned char *slow(register struct match *m, unsigned char *start, \
+ ==	unsigned char *stop, sopno startst, sopno stopst);
  */
-static char *			/* where it ended */
+static unsigned char *			/* where it ended */
 slow(m, start, stop, startst, stopst)
 register struct match *m;
-char *start;
-char *stop;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
 	register states st = m->st;
 	register states empty = m->empty;
 	register states tmp = m->tmp;
-	register char *p = start;
+	register unsigned char *p = start;
 	register int c = (start == m->beginp) ? OUT : *(start-1);
 	register int lastc;	/* previous c */
 	register int flagch;
 	register int i;
-	register char *matchp;	/* last p at which a match ended */
+	register unsigned char *matchp;	/* last p at which a match ended */
 
 	AT("slow", start, stop, startst, stopst);
 	CLEAR(st);
@@ -805,8 +805,8 @@ sopno stopst;
  == #define	BOW	(BOL+4)
  == #define	EOW	(BOL+5)
  == #define	CODEMAX	(BOL+5)		// highest code used
- == #define	NONCHAR(c)	((c) > CHAR_MAX)
- == #define	NNONCHAR	(CODEMAX-CHAR_MAX)
+ == #define	NONCHAR(c)	((c) > UCHAR_MAX)
+ == #define	NNONCHAR	(CODEMAX-UCHAR_MAX)
  */
 static states
 step(g, start, stop, bef, ch, aft)
@@ -832,8 +832,8 @@ register states aft;		/* states already known reachable after */
 			break;
 		case OCHAR:
 			/* only characters can match */
-			assert(!NONCHAR(ch) || ch != (char)OPND(s));
-			if (ch == (char)OPND(s))
+			assert(!NONCHAR(ch) || ch != (unsigned char)OPND(s));
+			if (ch == (unsigned char)OPND(s))
 				FWD(aft, bef, 1);
 			break;
 		case OBOL:
@@ -926,14 +926,14 @@ register states aft;		/* states already known reachable after */
 /*
  - print - print a set of states
  == #ifdef REDEBUG
- == static void print(struct match *m, char *caption, states st, \
+ == static void print(struct match *m, unsigned char *caption, states st, \
  ==	int ch, FILE *d);
  == #endif
  */
 static void
 print(m, caption, st, ch, d)
 struct match *m;
-char *caption;
+unsigned char *caption;
 states st;
 int ch;
 FILE *d;
@@ -959,16 +959,16 @@ FILE *d;
 /* 
  - at - print current situation
  == #ifdef REDEBUG
- == static void at(struct match *m, char *title, char *start, char *stop, \
+ == static void at(struct match *m, unsigned char *title, unsigned char *start, unsigned char *stop, \
  ==						sopno startst, sopno stopst);
  == #endif
  */
 static void
 at(m, title, start, stop, startst, stopst)
 struct match *m;
-char *title;
-char *start;
-char *stop;
+unsigned char *title;
+unsigned char *start;
+unsigned char *stop;
 sopno startst;
 sopno stopst;
 {
@@ -985,7 +985,7 @@ sopno stopst;
 /*
  - pchar - make a character printable
  == #ifdef REDEBUG
- == static char *pchar(int ch);
+ == static unsigned char *pchar(int ch);
  == #endif
  *
  * Is this identical to regchar() over in debug.c?  Well, yes.  But a
@@ -993,11 +993,11 @@ sopno stopst;
  * a matching debug.o, and this is convenient.  It all disappears in
  * the non-debug compilation anyway, so it doesn't matter much.
  */
-static char *			/* -> representation */
+static unsigned char *			/* -> representation */
 pchar(ch)
 int ch;
 {
-	static char pbuf[10];
+	static unsigned char pbuf[10];
 
 	if (isprint(ch) || ch == ' ')
 		sprintf(pbuf, "%c", ch);
diff --git a/regex/engine.ih b/regex/engine.ih
index cc98334e752..9a301838bcd 100644
--- a/regex/engine.ih
+++ b/regex/engine.ih
@@ -4,11 +4,11 @@ extern "C" {
 #endif
 
 /* === engine.c === */
-static int matcher(register struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
-static char *dissect(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
-static char *backref(register struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev);
-static char *fast(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
-static char *slow(register struct match *m, char *start, char *stop, sopno startst, sopno stopst);
+static int matcher(register struct re_guts *g, unsigned char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
+static unsigned char *dissect(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
+static unsigned char *backref(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst, sopno lev);
+static unsigned char *fast(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
+static unsigned char *slow(register struct match *m, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
 static states step(register struct re_guts *g, sopno start, sopno stop, register states bef, int ch, register states aft);
 #define	BOL	(OUT+1)
 #define	EOL	(BOL+1)
@@ -17,16 +17,16 @@ static states step(register struct re_guts *g, sopno start, sopno stop, register
 #define	BOW	(BOL+4)
 #define	EOW	(BOL+5)
 #define	CODEMAX	(BOL+5)		/* highest code used */
-#define	NONCHAR(c)	((c) > CHAR_MAX)
-#define	NNONCHAR	(CODEMAX-CHAR_MAX)
+#define	NONCHAR(c)	((c) > UCHAR_MAX)
+#define	NNONCHAR	(CODEMAX-UCHAR_MAX)
 #ifdef REDEBUG
-static void print(struct match *m, char *caption, states st, int ch, FILE *d);
+static void print(struct match *m, unsigned char *caption, states st, int ch, FILE *d);
 #endif
 #ifdef REDEBUG
-static void at(struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst);
+static void at(struct match *m, unsigned char *title, unsigned char *start, unsigned char *stop, sopno startst, sopno stopst);
 #endif
 #ifdef REDEBUG
-static char *pchar(int ch);
+static unsigned char *pchar(int ch);
 #endif
 
 #ifdef __cplusplus
diff --git a/regex/regcomp.c b/regex/regcomp.c
index 0b939461bd7..ec034d4c4ce 100644
--- a/regex/regcomp.c
+++ b/regex/regcomp.c
@@ -19,8 +19,8 @@
  * other clumsinesses
  */
 struct parse {
-	char *next;		/* next character in RE */
-	char *end;		/* end of string (-> NUL normally) */
+	unsigned char *next;		/* next character in RE */
+	unsigned char *end;		/* end of string (-> NUL normally) */
 	int error;		/* has an error been seen? */
 	sop *strip;		/* malloced strip */
 	sopno ssize;		/* malloced strip size (allocated) */
@@ -34,7 +34,7 @@ struct parse {
 
 #include "regcomp.ih"
 
-static char nuls[10];		/* place to point scanner in event of error */
+static unsigned char nuls[10];		/* place to point scanner in event of error */
 
 /*
  * macros for use with parse structure
@@ -127,7 +127,7 @@ int cflags;
 
 	/* set things up */
 	p->g = g;
-	p->next = (char *)pattern;	/* convenience; we do not modify it */
+	p->next = (unsigned char *)pattern;	/* convenience; we do not modify it */
 	p->end = p->next + len;
 	p->error = 0;
 	p->ncsalloc = 0;
@@ -147,7 +147,7 @@ int cflags;
 	g->mlen = 0;
 	g->nsub = 0;
 	g->ncategories = 1;	/* category 0 is "everything else" */
-	g->categories = &g->catspace[-(CHAR_MIN)];
+	g->categories = &g->catspace[0];
 	(void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
 	g->backrefs = 0;
 
@@ -193,7 +193,7 @@ p_ere(p, stop)
 register struct parse *p;
 int stop;			/* character this ERE should end at */
 {
-	register char c;
+	register unsigned char c;
 	register sopno prevback = 0;
 	register sopno prevfwd = 0;
 	register sopno conc;
@@ -238,7 +238,7 @@ static void
 p_ere_exp(p)
 register struct parse *p;
 {
-	register char c;
+	register unsigned char c;
 	register sopno pos;
 	register int count;
 	register int count2;
@@ -518,7 +518,7 @@ int starordinary;		/* is a leading * an ordinary character? */
 		REQUIRE(starordinary, REG_BADRPT);
 		/* FALLTHROUGH */
 	default:
-		ordinary(p, (char)c);	/* takes off BACKSL, if any */
+		ordinary(p, (unsigned char)c);	/* takes off BACKSL, if any */
 		break;
 	}
 
@@ -657,8 +657,8 @@ p_b_term(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char c;
-	register char start, finish;
+	register unsigned char c;
+	register unsigned char start, finish;
 	register int i;
 
 	/* classify what we've got */
@@ -723,11 +723,11 @@ p_b_cclass(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char *sp = p->next;
+	register unsigned char *sp = p->next;
 	register struct cclass *cp;
 	register size_t len;
-	register char *u;
-	register char c;
+	register unsigned char *u;
+	register unsigned char c;
 
 	while (MORE() && isalpha(PEEK()))
 		NEXT();
@@ -759,7 +759,7 @@ p_b_eclass(p, cs)
 register struct parse *p;
 register cset *cs;
 {
-	register char c;
+	register unsigned char c;
 
 	c = p_b_coll_elem(p, '=');
 	CHadd(cs, c);
@@ -769,11 +769,11 @@ register cset *cs;
  - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
  == static char p_b_symbol(register struct parse *p);
  */
-static char			/* value of symbol */
+static unsigned char			/* value of symbol */
 p_b_symbol(p)
 register struct parse *p;
 {
-	register char value;
+	register unsigned char value;
 
 	REQUIRE(MORE(), REG_EBRACK);
 	if (!EATTWO('[', '.'))
@@ -789,12 +789,12 @@ register struct parse *p;
  - p_b_coll_elem - parse a collating-element name and look it up
  == static char p_b_coll_elem(register struct parse *p, int endc);
  */
-static char			/* value of collating element */
+static unsigned char			/* value of collating element */
 p_b_coll_elem(p, endc)
 register struct parse *p;
 int endc;			/* name ended by endc,']' */
 {
-	register char *sp = p->next;
+	register unsigned char *sp = p->next;
 	register struct cname *cp;
 	register int len;
 
@@ -818,7 +818,7 @@ int endc;			/* name ended by endc,']' */
  - othercase - return the case counterpart of an alphabetic
  == static char othercase(int ch);
  */
-static char			/* if no counterpart, return ch */
+static unsigned char			/* if no counterpart, return ch */
 othercase(ch)
 int ch;
 {
@@ -842,9 +842,9 @@ bothcases(p, ch)
 register struct parse *p;
 int ch;
 {
-	register char *oldnext = p->next;
-	register char *oldend = p->end;
-	char bracket[3];
+	register unsigned char *oldnext = p->next;
+	register unsigned char *oldend = p->end;
+	unsigned char bracket[3];
 
 	assert(othercase(ch) != ch);	/* p_bracket() would recurse */
 	p->next = bracket;
@@ -888,9 +888,9 @@ static void
 nonnewline(p)
 register struct parse *p;
 {
-	register char *oldnext = p->next;
-	register char *oldend = p->end;
-	char bracket[4];
+	register unsigned char *oldnext = p->next;
+	register unsigned char *oldend = p->end;
+	unsigned char bracket[4];
 
 	p->next = bracket;
 	p->end = bracket+3;
@@ -1015,19 +1015,19 @@ register struct parse *p;
 		if (p->g->sets == NULL)
 			p->g->sets = (cset *)malloc(nc * sizeof(cset));
 		else
-			p->g->sets = (cset *)realloc((char *)p->g->sets,
+			p->g->sets = (cset *)realloc((unsigned char *)p->g->sets,
 							nc * sizeof(cset));
 		if (p->g->setbits == NULL)
 			p->g->setbits = (uch *)malloc(nbytes);
 		else {
-			p->g->setbits = (uch *)realloc((char *)p->g->setbits,
+			p->g->setbits = (uch *)realloc((unsigned char *)p->g->setbits,
 								nbytes);
 			/* xxx this isn't right if setbits is now NULL */
 			for (i = 0; i < no; i++)
 				p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT);
 		}
 		if (p->g->sets != NULL && p->g->setbits != NULL)
-			(void) memset((char *)p->g->setbits + (nbytes - css),
+			(void) memset((unsigned char *)p->g->setbits + (nbytes - css),
 								0, css);
 		else {
 			no = 0;
@@ -1120,7 +1120,7 @@ register cset *cs;
 
 	for (i = 0; i < css; i++)
 		if (CHIN(cs, i))
-			return((char)i);
+			return((unsigned char)i);
 	assert(never);
 	return(0);		/* arbitrary */
 }
@@ -1153,7 +1153,7 @@ static void
 mcadd(p, cs, cp)
 register struct parse *p;
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
 	register size_t oldend = cs->smultis;
 
@@ -1174,14 +1174,14 @@ register char *cp;
 #if 0
 /*
  - mcsub - subtract a collating element from a cset
- == static void mcsub(register cset *cs, register char *cp);
+ == static void mcsub(register cset *cs, register unsigned char *cp);
  */
 static void
 mcsub(cs, cp)
-register cset *cs;
-register char *cp;
+register unsigned cset *cs;
+register unsigned char *cp;
 {
-	register char *fp = mcfind(cs, cp);
+	register unsigned char *fp = mcfind(cs, cp);
 	register size_t len = strlen(fp);
 
 	assert(fp != NULL);
@@ -1201,12 +1201,12 @@ register char *cp;
 
 /*
  - mcin - is a collating element in a cset?
- == static int mcin(register cset *cs, register char *cp);
+ == static int mcin(register cset *cs, register unsigned char *cp);
  */
 static int
 mcin(cs, cp)
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
 	return(mcfind(cs, cp) != NULL);
 }
@@ -1214,14 +1214,14 @@ register char *cp;
 
 /*
  - mcfind - find a collating element in a cset
- == static char *mcfind(register cset *cs, register char *cp);
+ == static unsigned char *mcfind(register cset *cs, register unsigned char *cp);
  */
-static char *
+static unsigned char *
 mcfind(cs, cp)
 register cset *cs;
-register char *cp;
+register unsigned char *cp;
 {
-	register char *p;
+	register unsigned char *p;
 
 	if (cs->multis == NULL)
 		return(NULL);
@@ -1322,11 +1322,11 @@ register struct re_guts *g;
 	if (p->error != 0)
 		return;
 
-	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
+	for (c = 0; c <= UCHAR_MAX; c++)
 		if (cats[c] == 0 && isinsets(g, c)) {
 			cat = g->ncategories++;
 			cats[c] = cat;
-			for (c2 = c+1; c2 <= CHAR_MAX; c2++)
+			for (c2 = c+1; c2 <= UCHAR_MAX; c2++)
 				if (cats[c2] == 0 && samesets(g, c, c2))
 					cats[c2] = cat;
 		}
@@ -1477,7 +1477,7 @@ register struct parse *p;
 register struct re_guts *g;
 {
 	g->nstates = p->slen;
-	g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
+	g->strip = (sop *)realloc((unsigned char *)p->strip, p->slen * sizeof(sop));
 	if (g->strip == NULL) {
 		SETERROR(REG_ESPACE);
 		g->strip = p->strip;
@@ -1504,7 +1504,7 @@ register struct re_guts *g;
 	register sop *newstart = NULL;
 	register sopno newlen;
 	register sop s;
-	register char *cp;
+	register unsigned char *cp;
 	register sopno i;
 
 	/* avoid making error situations worse */
@@ -1565,7 +1565,7 @@ register struct re_guts *g;
 		while (OP(s = *scan++) != OCHAR)
 			continue;
 		assert(cp < g->must + g->mlen);
-		*cp++ = (char)OPND(s);
+		*cp++ = (unsigned char)OPND(s);
 	}
 	assert(cp == g->must + g->mlen);
 	*cp++ = '\0';		/* just on general principles */
diff --git a/regex/regcomp.ih b/regex/regcomp.ih
index 6efafebf602..c93d32e51d3 100644
--- a/regex/regcomp.ih
+++ b/regex/regcomp.ih
@@ -14,9 +14,9 @@ static void p_bracket(register struct parse *p);
 static void p_b_term(register struct parse *p, register cset *cs);
 static void p_b_cclass(register struct parse *p, register cset *cs);
 static void p_b_eclass(register struct parse *p, register cset *cs);
-static char p_b_symbol(register struct parse *p);
-static char p_b_coll_elem(register struct parse *p, int endc);
-static char othercase(int ch);
+static unsigned char p_b_symbol(register struct parse *p);
+static unsigned char p_b_coll_elem(register struct parse *p, int endc);
+static unsigned char othercase(int ch);
 static void bothcases(register struct parse *p, int ch);
 static void ordinary(register struct parse *p, register int ch);
 static void nonnewline(register struct parse *p);
@@ -27,11 +27,11 @@ static void freeset(register struct parse *p, register cset *cs);
 static int freezeset(register struct parse *p, register cset *cs);
 static int firstch(register struct parse *p, register cset *cs);
 static int nch(register struct parse *p, register cset *cs);
-static void mcadd(register struct parse *p, register cset *cs, register char *cp);
+static void mcadd(register struct parse *p, register cset *cs, register unsigned char *cp);
 #if 0
-static void mcsub(register cset *cs, register char *cp);
-static int mcin(register cset *cs, register char *cp);
-static char *mcfind(register cset *cs, register char *cp);
+static void mcsub(register cset *cs, register unsigned char *cp);
+static int mcin(register cset *cs, register unsigned char *cp);
+static unsigned char *mcfind(register cset *cs, register unsigned char *cp);
 #endif
 static void mcinvert(register struct parse *p, register cset *cs);
 static void mccase(register struct parse *p, register cset *cs);
diff --git a/regex/regex2.h b/regex/regex2.h
index 7cd39a59ae5..4996f96ecd3 100644
--- a/regex/regex2.h
+++ b/regex/regex2.h
@@ -10,7 +10,7 @@
  = typedef struct {
  = 	int re_magic;
  = 	size_t re_nsub;		// number of parenthesized subexpressions
- = 	const char *re_endp;	// end pointer for REG_PEND
+ = 	const unsigned char *re_endp;	// end pointer for REG_PEND
  = 	struct re_guts *re_g;	// none of your business :-)
  = } regex_t;
  = typedef struct {
@@ -90,7 +90,7 @@ typedef struct {
 	uch mask;		/* bit within array */
 	uch hash;		/* hash code */
 	size_t smultis;
-	char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
+	unsigned char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
 } cset;
 /* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
 #define	CHadd(cs, c)	((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
@@ -125,8 +125,8 @@ struct re_guts {
 	int nbol;		/* number of ^ used */
 	int neol;		/* number of $ used */
 	int ncategories;	/* how many character categories */
-	cat_t *categories;	/* ->catspace[-CHAR_MIN] */
-	char *must;		/* match must contain this string */
+	cat_t *categories;	/* ->catspace[-UCHAR_MIN] */
+	unsigned char *must;		/* match must contain this string */
 	int mlen;		/* length of must */
 	size_t nsub;		/* copy of re_nsub */
 	int backrefs;		/* does it use back references? */
@@ -136,5 +136,5 @@ struct re_guts {
 };
 
 /* misc utilities */
-#define	OUT	(CHAR_MAX+1)	/* a non-character value */
+#define	OUT	(UCHAR_MAX+1)	/* a non-character value */
 #define	ISWORD(c)	(isalnum(c) || (c) == '_')
diff --git a/regex/regexec.c b/regex/regexec.c
index 7888d02368c..c8cb8fdf564 100644
--- a/regex/regexec.c
+++ b/regex/regexec.c
@@ -67,14 +67,14 @@ static int nope = 0;		/* for use in asserts; shuts lint up */
 #undef	SNAMES
 
 /* macros for manipulating states, large version */
-#define	states	char *
+#define	states	unsigned char *
 #define	CLEAR(v)	memset(v, 0, m->g->nstates)
 #define	SET0(v, n)	((v)[n] = 0)
 #define	SET1(v, n)	((v)[n] = 1)
 #define	ISSET(v, n)	((v)[n])
 #define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
 #define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
-#define	STATEVARS	int vn; char *space
+#define	STATEVARS	int vn; unsigned char *space
 #define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
 				if ((m)->space == NULL) return(REG_ESPACE); \
 				(m)->vn = 0; }
@@ -132,7 +132,7 @@ int eflags;
 	eflags = GOODFLAGS(eflags);
 
 	if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
-		return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
+		return(smatcher(g, (unsigned char *)string, nmatch, pmatch, eflags));
 	else
-		return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
+		return(lmatcher(g, (unsigned char *)string, nmatch, pmatch, eflags));
 }