[PATCH] posix: Fix improper assert in Linux posix_spawn (BZ#22273)

[Florian Weimer]

On 10/18/2017 07:34 PM, Adhemerval Zanella wrote:
>> We could probably do better if we called clone without SIGCHLD.  Not sure if that works, but it's a different enhancement and out of scope for this patch.  If Andreas is happy with what you've got, so am I.

> I do not think this scenario would help much because caller can still
> use a child handler using Linux only flags (__WALL or __WCLONE).

I was wrong: we need to specify SIGCHLD to get the right semantics for 
the success case.

Internal vfork for system and perhaps popen could use this because these 
interfaces do not expose the PID, but not posix_spawn.

Thanks,
Florian