Re: [PATCH] Add facility to collect stderr of async subprocess

[Tino Calancha <tino.calancha@gmail.com>]

On Thu, 6 Oct 2016, Eli Zaretskii wrote:

>> From: Tino Calancha <tino.calancha@gmail.com>
>> Date: Thu, 6 Oct 2016 12:13:11 +0900 (JST)
>>
>> We have an entry in the TODO list requesting exactly what i am
>> suggesting :-)
>
> It's an old item (from 2004), written before we had make-process.
> Thanks for pointing this out.
>
>> Question:
>> can we conclude that following entry in TODO file has being
>> fulfilled by Daiki work?
>
> Yes, I think so.
I agree : i also think the idea underneath such TODO entry
matches what Daiki san did.

By the way, i am fine if we don't follow my suggestion.
I just want to remark that my patch repect backward compatibility:
callers passing a buffer will get the traditional behaviour.
It is just in case we pass a list that we will separate
the stderr from stdout.
As a bonus, several other functions will automatically inherit this 
feature: `start-file-process', `start-process-shell-command', and 
`start-file-process-shell-command'.
Personally, i find pleasant if every function creating an asynchronous 
process us able to separate stdout from stderr.

Another minor thing is that my patch fix a bug in async-shell-command:
current implementation don't use the second optional argument 
ERROR-BUFFER.  Of course, that could be fixed using `make-process'.