bug#17666: 24.3.91; [regression] call-process in read-only buffers

[Eli Zaretskii]

> Date: Mon, 02 Jun 2014 13:45:25 -0400
> Cc: 17666@debbugs.gnu.org
> 
> Anyway, it's the prepare_to_modify_buffer in call_process what does it.

Actually, I think the problem is that the code there calls
decode_coding_c_string even if we read zero bytes from the process.
With some coding-systems, this will insert something into the buffer,
so the call to prepare_to_modify_buffer is justified.

But I agree that the previous behavior was sweeping a subtle bug under
the carpet.