[issue20104] expose posix_spawn(p)

[Serhiy Storchaka]

Change by Serhiy Storchaka <storchaka+cpython at gmail.com>:


----------
dependencies: +Expose the sigset_t converter via private API

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue20104>
_______________________________________