bug#35576: 27.0.50; Emacs crash when reads an integer with radix > 36

[Eli Zaretskii]

> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sun, 05 May 2019 20:37:08 +0900
> 
> emacs -Q:
> ;; Emacs crash when you eval the following form
> M-: #37r1
> 
> ;; Expected: you get the error:
> ;; Invalid read syntax: "integer, radix 37"
> 
> 
> 
> In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
>  of 2019-05-05
> Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
> System Description: Debian GNU/Linux 9 (stretch)
> 
> 
> --8<-----------------------------cut 
> here---------------start------------->8---
> commit c5ffba787a10f80d17a0ebc7fc7e1fb0f754843d
> Author: Tino Calancha <tino.calancha@gmail.com>
> Date:   Sun May 5 20:24:03 2019 +0900
> 
>     src/lread.c (read_integer): Prevent from accessing a null buffer

Thanks, I installed a slightly different fix (there's no need to call
xfree, since record_unwind_protect_ptr already takes care of that).