The patch fixes a symptom of wrong format specs usage. What happens with %s with no supplied arg depends on the platform and what is currently on the stack. So it will always be incorrect and you can't do anything about it except for letting the gettext tools checking the PO files for correct format specifier usage. In the english version gcc does the check.

However, while looking at that case I found a slight discrepant between using less than 8 format specifiers and using more. In the latter case the VALUETABLE is allocate using calloc and thus everything is cleared. In the former case only the .vt member is cleared and the other members are not initialized. That is still okay but to avoid surprises I would suggest to clear them all out. This should be done later in the function; something like

   valuetable[validx].vt = VALTYPE_UNSUPPORTED;
+  memset (valuetable[validx].value, 0, sizeof *(valuetable[validx].value));