[PATCH] Cygwin: pty: Introduce disable_pcon in environment CYGWIN.

[Ken Brown]

[Adding the cgdb maintainer to the CC.]

On 1/20/2020 9:18 AM, Jon Turney wrote:
> On 20/01/2020 12:41, Takashi Yano wrote:
>> Hi Corinna,
>>
>> On Mon, 20 Jan 2020 11:06:46 +0100
>> Corinna Vinschen wrote:
>>> On Jan 20 11:50, Takashi Yano wrote:
>>>> - For programs which does not work properly with pseudo console,
>>>>    disable_pcon in environment CYGWIN is introduced. If disable_pcon
>>>>    is set, pseudo console support is disabled.
>>> Oh well, do we really need that?
>>
>> This is, for example, needed to solve the issue reported in
>> https://www.cygwin.com/ml/cygwin/2020-01/msg00147.html.
>>
>> I looked into this problem, and found that cgdb read output of
>> gdb from pty master and write it to ncurses. The output from
>> pty master includes a lot of escape sequences which are generated
>> by pseudo console, however, ncurses does not pass-through them
>> and shows garbages. This is the cause of that issue.
>>
>> cgdb is the only program do such things so far, however, there
>> may be more programs which do not expect escape sequences read
>> from pty.
>>
>> There is no way to control pseudo console not to generate
>> escape sequences, therefore, I proposed this patch.
>>
> 
> I think this may actually be an issue with cgdb being old.
> 
> The latest gdb enables "output styling" using ANSI escape sequences by default, 
> but our cgdb can't handle them?
> 
> See: https://github.com/cgdb/cgdb/issues/211