Hello Python list, I intend to cross-compile Python v3.6.6 to Threos ( https://threos.io ) operating system. Threos is supports a quite large set from POSIX and C89/C99. Unfortunately, Threos lacks fork(2), but provides posix_spawn(3) instead. I already made some local changes in posixmodule.c to compile due to some features are detected as present but actually not supported, like HAVE_FORK -- I blame autotools for this :-). I don't know, however, whether the Python shall cross-compile without issues. My question is that the _posixsubprocess.c can be prepared to use posix_spawn(3) instead of fork(2)? Maybe the UNIX/Linux version can also benefit from it, see: https://salsa.debian.org/ruby-team/ruby-posix-spawn Best regards, Aron