All the file actions stuff is still missing for now,
as is POSIX_SPAWN_SETSCHEDULER (not sure what that's
supposed to do) and POSIX_SPAWN_RESETIDS.
Implemented in userspace for now. Once there are users,
it'll likely make sense to make this a syscall for
performance reasons.
A simple test program of the form
extern char **environ;
int main(int argc, char* argv[])
{
pid_t pid;
char* args[] = { "ls", NULL };
posix_spawnp(&pid, "ls", nullptr, nullptr, args, environ);
}
works fine.