Bug#1133513: libe-book: ftbfs with GCC-16

Hi,

Am 13.04.26 um 19:06 schrieb Rene Engelhard:
> Hi,
> 
> Am 13.04.26 um 18:53 schrieb Rene Engelhard:
>>
>> Maybe. Or this is another case of what plagued libreoffice and was worked around with
>>
>> https://salsa.debian.org/libreoffice-team/libreoffice/libreoffice/-/blob/master/patches/gcc16.diff?ref_type=heads#L59 ff. and
> 
> See also upstreams https://gerrit.libreoffice.org/c/core/+/202511/comments/b6a92d32_0c72b450 and following comments...
> 
> And indeed the same happens:
> 
> checking how to run the C++ preprocessor... g++ -std=gnu++11 -E
> checking for ld used by g++ -std=gnu++11... /usr/bin/x86_64-linux-gnu-ld -m elf_x86_64
> checking if the linker (/usr/bin/x86_64-linux-gnu-ld -m elf_x86_64) is GNU ld... yes
> checking whether the g++ -std=gnu++11 linker (/usr/bin/x86_64-linux-gnu-ld -m elf_x86_64) supports shared libraries... yes
> checking for g++ -std=gnu++11 option to produce PIC... -fPIC -DPIC
> checking if g++ -std=gnu++11 PIC flag -fPIC -DPIC works... yes
> checking if g++ -std=gnu++11 static flag -static works... yes
> checking if g++ -std=gnu++11 supports -c -o file.o... yes
> checking if g++ -std=gnu++11 supports -c -o file.o... (cached) yes
> checking whether the g++ -std=gnu++11 linker (/usr/bin/x86_64-linux-gnu-ld -m elf_x86_64) supports shared libraries... yes
> checking dynamic linker characteristics... (cached) GNU/Linux ld.so
> checking how to hardcode library paths into programs... immediate
> checking whether g++ -std=gnu++11 supports C++11 features by default... yes
> 
> Looks like it.
> 
> That of course breaks. Now the question is why autoconf unhelpfully adds that with gcc 16...
> CC'ing the autoconf maintainer. I see 2.72-6 removing debian/patches/fix-cxx-stdcxx-test.diff but according to the debdiff it was not applied before anyway...
> 
> That might also be the explanation for a loads of other gcc 16 FTBFS....

# work around autoconf unhelpfully adding -std=gnu++11 which breaks with gcc 16
SYSTEM_GCC_VERSION = $(shell gcc --version | sed -n '/^gcc/s/.*\(..\..\)\../\1/p' | cut -d" " -f1 | cut -d. -f1)
ifeq "$(shell test $(SYSTEM_GCC_VERSION) -ge 16 && echo true)" "true"
export DEB_CXXFLAGS_MAINT_APPEND += -std=gnu++17
endif

in debian/rules in libe-book works but that of course is extremely ugly...

Regards,


Rene