diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c1d19a829a..f0abc8706f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2015-03-20  Pedro Alves  <palves@redhat.com>
+
+	* tui/tui-io.c (tui_expand_tabs): Make "s1" const.
+
 2015-03-20  Pedro Alves  <palves@redhat.com>
 
 	* xcoffread.c (scan_xcoff_symtab): Make "p" and "q" const.
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index a8af9b6116..c8b85672c0 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -692,7 +692,7 @@ tui_expand_tabs (const char *string, int col)
   /* 2. Copy the original string while replacing TABs with spaces.  */
   for (s = string; s; )
     {
-      char *s1 = strpbrk (s, "\t");
+      const char *s1 = strpbrk (s, "\t");
       if (s1)
 	{
 	  if (s1 > s)