diff --git a/gettext-tools/src/cldr-plurals.c b/gettext-tools/src/cldr-plurals.c
index e5bf06f43..da4eccf18 100644
--- a/gettext-tools/src/cldr-plurals.c
+++ b/gettext-tools/src/cldr-plurals.c
@@ -158,7 +158,7 @@ extract_rules (FILE *fp,
 
   {
     /* Scrub the last semicolon, if any.  */
-    char *p = strrchr (sb_xcontents_c (&buffer), ';');
+    char *p = strrchr ((char *) sb_xcontents_c (&buffer), ';');
     if (p)
       *p = '\0';
   }
diff --git a/libtextstyle/gnulib-local/lib/glib/gstrfuncs.c b/libtextstyle/gnulib-local/lib/glib/gstrfuncs.c
index e66e03176..d6bd1cc42 100644
--- a/libtextstyle/gnulib-local/lib/glib/gstrfuncs.c
+++ b/libtextstyle/gnulib-local/lib/glib/gstrfuncs.c
@@ -1,5 +1,5 @@
 /* GLIB - Library of useful routines for C programming
- * Copyright (C) 2006-2024 Free Software Foundation, Inc.
+ * Copyright (C) 2006-2026 Free Software Foundation, Inc.
  *
  * This file is not part of the GNU gettext program, but is used with
  * GNU gettext.
@@ -2610,7 +2610,7 @@ g_strjoin (const gchar  *separator,
  * Return value: a pointer to the found occurrence, or
  *    %NULL if not found.
  **/
-gchar *
+const gchar *
 g_strstr_len (const gchar *haystack,
 	      gssize       haystack_len,
 	      const gchar *needle)
diff --git a/libtextstyle/gnulib-local/lib/glib/gstrfuncs.in.h b/libtextstyle/gnulib-local/lib/glib/gstrfuncs.in.h
index 15c96a020..a5cb2cd9a 100644
--- a/libtextstyle/gnulib-local/lib/glib/gstrfuncs.in.h
+++ b/libtextstyle/gnulib-local/lib/glib/gstrfuncs.in.h
@@ -1,5 +1,5 @@
 /* GLIB - Library of useful routines for C programming
- * Copyright (C) 2006-2019 Free Software Foundation, Inc.
+ * Copyright (C) 2006-2026 Free Software Foundation, Inc.
  *
  * This file is not part of the GNU gettext program, but is used with
  * GNU gettext.
@@ -124,7 +124,7 @@ gsize	              g_strlcat        (gchar	     *dest,
 					const gchar  *src,
 					gsize         dest_size);
 #endif
-gchar *               g_strstr_len     (const gchar  *haystack,
+const gchar *         g_strstr_len     (const gchar  *haystack,
 					gssize        haystack_len,
 					const gchar  *needle);
 #if 0
diff --git a/libtextstyle/gnulib-local/lib/libcroco/cr-rgb.c b/libtextstyle/gnulib-local/lib/libcroco/cr-rgb.c
index c02387fe1..62fa584c1 100644
--- a/libtextstyle/gnulib-local/lib/libcroco/cr-rgb.c
+++ b/libtextstyle/gnulib-local/lib/libcroco/cr-rgb.c
@@ -1,7 +1,7 @@
 /* -*- Mode: C; indent-tabs-mode:nil; c-basic-offset: 8-*- */
 
 /* libcroco - Library for parsing and applying CSS
- * Copyright (C) 2006-2019 Free Software Foundation, Inc.
+ * Copyright (C) 2006-2026 Free Software Foundation, Inc.
  *
  * This file is not part of the GNU gettext program, but is used with
  * GNU gettext.
@@ -483,7 +483,7 @@ enum CRStatus
 cr_rgb_set_from_name (CRRgb * a_this, const guchar * a_color_name)
 {
         enum CRStatus status = CR_OK;
-        CRRgb *result;
+        CRRgb const *result;
 
         g_return_val_if_fail (a_this && a_color_name, CR_BAD_PARAM_ERROR);