bug#69795: 29.1; cmdproxy.exe exits automatically after executing MSYS2 commands

[Eli Zaretskii <eliz@gnu.org>]

> From: awrhygty@outlook.com
> Cc: 69795@debbugs.gnu.org
> Date: Mon, 18 Mar 2024 10:24:59 +0900
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > So one of these two directories somehow triggers the problem?  Or do
> > you need both on PATH to trigger the problem, and if you only add
> > either one of them, the problem does not happen?
> 
> c:\msys64\usr\bin\ matters. And iconv.exe under it makes the difference.
> In the log below, the process continues after the first call of gdb.exe,
> while iconv.exe does not exist.
> And the process finishes after the second call of gdb.exe,
> while iconv.exe exists.

So what is special with iconv.exe?  What does "iconv --version" say?
Also, what DLLs does it load?  You can find out like this:

  objdump -x c:\msys64\usr\bin\iconv.exe | grep -F "DLL Name:"

And if you invoke iconv.exe from the shell buffer directly, does it
also cause "Process shell finished"?