Bug#742818: fix test failures when built with GCC 4.9

[Niko Tyni]

On Sun, Mar 30, 2014 at 02:21:05PM +0300, Niko Tyni wrote:
> forwarded 742818 https://rt.perl.org/Ticket/Display.html?id=121505
> thanks

> > >>>>   * Fix undefined behaviour in sv.c, resulting in test failures when
> > >>>>     built with GCC 4.9. Patch by Marek Polacek.
 
> Marek also supplied fixes for other similar cases of undefined behaviour,
> and those were present in the 5.18.2-2ubuntu1 patch.
> 
> I'll wait a while for upstream to comment, but I expect this will be in
> our next upload.

While there isn't much discussion in the ticket, there were some around
 http://www.nntp.perl.org/group/perl.perl5.porters/2014/03/msg214103.html 
 
There's a concern that this problem is more widespread. Upstream is
considering enabling the gcc '-fwrapv' option to get the desired
behaviour in such cases.
-- 
Niko Tyni   ntyni at debian.org