[luatex] Segmentation fault by catcode table >= 0x8000

[Hironori KITAGAWA]

Hello all, 

The following source causes a Segmentation fault on LuaLaTeX (r4486):

---- test.tex ---
\documentclass{article}
\begin{document}
\chardef\tmpcctb"8000
\luatexinitcatcodetable\tmpcctb
\directlua{tex.print(\the\tmpcctb, 'a')}
\end{document}
----

I found the catcode table index is only signed short, and 
I think this is the cause of a Segfault. 

>    signed int cattable_field:16; 
  (inputstack.h l.37)
>    line_catcode_table = (short) luacstring_cattable();
  (textoken.w, l.1281)

If I replaced these two lines by the following respectively,
the above test.tex can be processed without error.
>    int cattable_field;
>    line_catcode_table = luacstring_cattable();
(Perhaps we also need "check_cattable_range()" in ltexlib.c)

Regards 
Hironori KITAGAWA <h_kitagawa2001 at yahoo.co.jp>