[PATCH] Always do locking when accessing streams (bug 15142)

[Florian Weimer]

* Andreas Schwab:

> During exit, skip files that are currently locked to avoid deadlock.

Which locks are taken during the deadlock?

Does this fix or re-open bug 15142?

> +  /* We want to skip locked streams.  Some threads might use streams but
> +     that is their problem, we don't flush those.  */
> +  int result = _IO_flush_all_lockp (true);

Is this still conforming to POSIX?

Sorry, it's not clear to me how this patch improves matters, and if the
direction is ultimately the right one.

Thanks,
Florian