windows_subsystem was declared nowhere, so the app carried a console
window on Windows. The file logger is unaffected; only the inherited
stdio console goes.
The offscreen smoke gate has not run against this yet. If smoke.log comes
back empty the fix is AttachConsole(ATTACH_PARENT_PROCESS) behind
cfg(windows), not reverting this; there is a note at the attribute saying
so.
cc
vicrodh
3e8a1cf942