[PATCH] Fix `Bad address` when running `cmd /c [...]`

[Takashi Yano]

On Fri, 21 Oct 2022 23:37:35 +0200 (CEST)
Johannes Schindelin wrote:
> In 2b4f986e49 (Cygwin: pty: Treat *.bat and *.cmd as a non-cygwin
> console app., 2022-07-31), we introduced a bug fix that specifically
> looks for a suffix of the command's file name.
> 
> However, that file name might be set to `NULL`, namely when
> `null_app_name == true`, which is the case when we detected a
> command-line `cmd /c [...]`.

It seems that this is msys2 specific issue.
I also noticed that
cmd //c 'echo AAA' instead of cmd /c 'echo AAA' works in msys2.

In cygwin, filename is
C:\WINDOWS\system32\cmd.exe
for cmd /c 'echo AAA'.

Why the filename can be NULL in msys2 in the case of cmd /c 'echo AAA'?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>