launcher: Fix displaying stderr in CLI mode. * binary-dist-rules.mk: Remove `-Wl,--subsystem,windows` from compiler flags. It looks like that prevents output to stderr from showing up at all. * installer-files/octave-launch.c: Only try to attach to the parents console if the flags explicitly require a CLI. Explicitly detach from any parent console otherwise. Create the Octave process explicitly without console Window unless the flags requested it. Unrelated: Pass the environment variables as Unicode to the Octave process. See also: https://octave.discourse.group/t/4689

mxe.cc