[Debian-med-packaging] Bug#831126: vxl: FTBFS with GCC 6: vcl_compiler.h:127:4: error: #error "Dunno about this gcc"

[Lucas Nussbaum]

Source: vxl
Version: 1.17.0.dfsg2-4
Severity: serious
Tags: stretch sid
User: debian-qa at lists.debian.org
Usertags: qa-ftbfs-20160713 qa-ftbfs
Justification: FTBFS with GCC 6 on amd64

Hi,

During a rebuild of all packages in sid using the gcc-defaults package
available in experimental to make GCC default to version 6, your package failed
to build on amd64. For more information about GCC 6 and Stretch, see:
- https://wiki.debian.org/GCC6
- https://lists.debian.org/debian-devel-announce/2016/06/msg00007.html

Relevant part (hopefully):
> make[3]: Entering directory '/«PKGBUILDDIR»/obj-x86_64-linux-gnu'
> [  0%] Building CXX object vcl/CMakeFiles/vcl.dir/vcl_deprecated.o
> cd /«PKGBUILDDIR»/obj-x86_64-linux-gnu/vcl && /usr/bin/c++   -DVXL_LEGACY_ERROR_REPORTING -DVXL_WARN_DEPRECATED -DVXL_WARN_DEPRECATED_ONCE -Dvcl_EXPORTS -I/«PKGBUILDDIR»/obj-x86_64-linux-gnu/vcl -I/«PKGBUILDDIR»/vcl -I/«PKGBUILDDIR»/obj-x86_64-linux-gnu/core -I/«PKGBUILDDIR»/core  -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2   -fPIC   -o CMakeFiles/vcl.dir/vcl_deprecated.o -c /«PKGBUILDDIR»/vcl/vcl_deprecated.cxx
> In file included from /«PKGBUILDDIR»/vcl/vcl_iosfwd.h:8:0,
>                  from /«PKGBUILDDIR»/vcl/vcl_iostream.h:27,
>                  from /«PKGBUILDDIR»/vcl/vcl_deprecated.cxx:4:
> /«PKGBUILDDIR»/vcl/vcl_compiler.h:127:4: error: #error "Dunno about this gcc"
>  #  error "Dunno about this gcc"
>     ^~~~~
> make[3]: *** [vcl/CMakeFiles/vcl.dir/vcl_deprecated.o] Error 1

The full build log is available from:
   http://people.debian.org/~lucas/logs/2016/07/13/vxl_1.17.0.dfsg2-4_unstable_gcc6.log

A list of current common problems and possible solutions is available at
http://wiki.debian.org/qa.debian.org/FTBFS . You're welcome to contribute!

About the archive rebuild: The rebuild was done on EC2 VM instances from
Amazon Web Services, using a clean, minimal and up-to-date chroot. Every
failed build was retried once to eliminate random failures.