Bug#746890: perl: ftbfs with GCC-4.9

[Niko Tyni]

On Sun, May 04, 2014 at 08:52:24AM +0100, Dominic Hargreaves wrote:
> Control: forwarded -1 https://rt.perl.org/Ticket/Display.html?id=121505
> Control: tags -1 +fixed-upstream
> 
> On Sun, May 04, 2014 at 12:22:21AM +0000, Matthias Klose wrote:
> > The package fails to build in a test rebuild on at least amd64 with
> > gcc-4.9/g++-4.9, but succeeds to build with gcc-4.8/g++-4.8. The
> > severity of this report may be raised before the jessie release.
> 
> Thanks for the report.
> 
> This is fixed upstream for 5.20, which we're targetting for jessie
> (releasing in the next month or so), so I think we don't need to do any
> particular work in advance of that.

On debian-release [1], Matthias writes that

  If anything goes well, and a large amount of build failures are fixed,
  I plan to make GCC 4.9 the default for the C/C++/ObjC/Obj-C++ frontends
  at the end of May, beginning of June.

I doubt we can get Perl 5.20 in sid by that time, so I suppose we need
to do something about 5.18 too. The options I see are

- explicitly use gcc-4.8
- apply the patch by Marek Polacek that upstream rejected in favour of
  -fwrapv (AIUI)
- backport the 5.20 -fwrapv changes in Configure
- force feed -fwrapv to ccflags Configure invocation in debian/config.debian

The last one seems easiest.

[1] https://lists.debian.org/debian-release/2014/05/msg00086.html
-- 
Niko