--- Tk-804.036/objGlue.c.orig
+++ Tk-804.036/objGlue.c
@@ -627,7 +627,7 @@
  sv_utf8_downgrade(objPtr, 0);
  if (lengthPtr)
   {
-   return (unsigned char *) SvPV(objPtr, *lengthPtr);
+   return (unsigned char *) SvPV(objPtr, *(STRLEN * const)lengthPtr);
   }
  else
   {