bug#7842: 23.2; call-process should be able to send stderr to buffer object

[Glenn Morris <rgm@gnu.org>]

Jameson Rollins wrote:

> Currently the call-process function lets one send stderr to a file by
> providing a list as the BUFFER argument which includes the name of a
> STDERR-FILE:
>
> (call-process "ls" nil (list t "/path/to/stderr/file") nil "/does-not-exist")
>
> It would be nice if one could instead send stderr directly to a distinct
> buffer, i.e.:

Quoth the elisp manual:

   "Creating a Synchronous Process"

    You can't directly specify a buffer to put the error output
    in; that is too difficult to implement.  But you can achieve
    this result by sending the error output to a temporary file
    and then inserting the file into a buffer.