[PATCH 0/6] MR8655: Cmd engine rewrite (part XXXII)

[eric pouech (＠epo)]

This MR mainly tackle the exit code generated from running
cmd.exe with /c command line option.
Things are a little bit torturous (as shown by tests) and
require a bit of refactoring.
The /k option is not covered as the tests trigger other bugs
that we'll need to tackle beforehand (mainly proper escaping
when rewriting builtin commands in pipe, that we'll need
also for real pipes implementation, and also some echo
features).