[PATCH 4/6] Do not call _xend if no transaction is active.

[Torvald Riegel]

On Mon, 2013-09-02 at 10:04 +0200, Dominik Vogt wrote:
> -    _xend();
> +    if (_xtest () != 0)
> +      _xend ();
> 

I disagree with this change (see my other email for details).  If we add
such a change in the future because we see that lots of people write
buggy programs (and they incorrectly blame glibc for it), then at the
very least we should fail visibly here, not silent.  That is, this
should have an else branch that does something like we do for
error-checking mutexes.