From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Adrian Ratiu <adrian.ratiu@collabora.com>
Date: Thu, 7 May 2026 17:00:00 +0000
Subject: [PATCH] third_party/utf: fix const-correctness exposed by glibc 2.43

glibc 2.43 makes strchr/strrchr/strstr preserve const via _Generic
macros. utfrune/utfrrune/utfutf pass a const char *s straight through
those functions but are declared to return char *, which now fails
-Werror.

Change the three return types (and their utf.h prototypes) to const
char * to match what they return, dropping two now-redundant (char *)
casts. No external callers exist in the tree (re2 and libphonenumber
bundle their own utf copies).

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
 third_party/utf/src/include/utf.h | 6 +++---
 third_party/utf/src/utf/utfrrune.c | 4 ++--
 third_party/utf/src/utf/utfrune.c  | 2 +-
 third_party/utf/src/utf/utfutf.c   | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/third_party/utf/src/include/utf.h b/third_party/utf/src/include/utf.h
--- a/third_party/utf/src/include/utf.h
+++ b/third_party/utf/src/include/utf.h
@@ -26,9 +26,9 @@ int charntorune(Rune*, const char*, size_t);
 int runetochar(char*, const Rune*);
 size_t utflen(const char*);
 size_t utfnlen(const char*, size_t);
-char* utfrune(const char*, Rune);
-char* utfrrune(const char*, Rune);
-char* utfutf(const char*, const char*);
+const char* utfrune(const char*, Rune);
+const char* utfrrune(const char*, Rune);
+const char* utfutf(const char*, const char*);
 char* utfecpy(char*, char*, const char*);

 int isalnumrune(Rune);
diff --git a/third_party/utf/src/utf/utfrrune.c b/third_party/utf/src/utf/utfrrune.c
--- a/third_party/utf/src/utf/utfrrune.c
+++ b/third_party/utf/src/utf/utfrrune.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include "utf.h"

-char *
+const char *
 utfrrune(const char *s, Rune r)
 {
 	const char *p = NULL;
@@ -17,5 +17,5 @@ utfrrune(const char *s, Rune r)
 		if(r == r0)
 			p = s;
 	}
-	return (char *)p;
+	return p;
 }
diff --git a/third_party/utf/src/utf/utfrune.c b/third_party/utf/src/utf/utfrune.c
--- a/third_party/utf/src/utf/utfrune.c
+++ b/third_party/utf/src/utf/utfrune.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include "utf.h"

-char *
+const char *
 utfrune(const char *s, Rune r)
 {
 	char buf[UTFmax+1];
diff --git a/third_party/utf/src/utf/utfutf.c b/third_party/utf/src/utf/utfutf.c
--- a/third_party/utf/src/utf/utfutf.c
+++ b/third_party/utf/src/utf/utfutf.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include "utf.h"

-char *
+const char *
 utfutf(const char *s1, const char *s2)
 {
 	const char *p;
@@ -16,7 +16,7 @@ utfutf(const char *s1, const char *s2)
 	n2 = strlen(s2);
 	for(p = s1; (p = utfrune(p, r)); p += n1)
 		if(!strncmp(p, s2, n2))
-			return (char *)p;
+			return p;

 	return NULL;
 }