diff -up texinfo-4.13/makeinfo/sectioning.c.orig texinfo-4.13/makeinfo/sectioning.c

--- texinfo-4.13/makeinfo/sectioning.c.orig	2010-11-10 11:24:53.000000000 +0100

+++ texinfo-4.13/makeinfo/sectioning.c	2010-11-10 11:25:28.000000000 +0100

@@ -256,14 +256,14 @@ current_chapter_number (void)

     return xstrdup ("");

   else if (enum_marker == APPENDIX_MAGIC)

     {

-      char s[1];

+      char s[2];

       sprintf (s, "%c", numbers[0] + 64);

       return xstrdup (s);

     }

   else

     {

       char s[5];

-      sprintf (s, "%d", numbers[0]);

+      sprintf (s, "%4d", numbers[0]);

       return xstrdup (s);

     }

 }