On 29.06.2017 06:51, Adrian Bunk wrote: > Package: libstdc++6 > Version: 7.1.0-7 > Severity: serious > Control: affects -1 src:mesa > > mesa FTBFS on armel due to: > > https://buildd.debian.org/status/fetch.php?pkg=mesa&arch=armel&ver=17.1.3-2&stamp=1498610882&raw=0 > > ... > llvm-config-4.0: relocation error: > /usr/lib/llvm-4.0/bin/../lib/libLLVM-4.0.so.1: symbol > _ZTINSt13__future_base12_Result_baseE, version GLIBCXX_3.4.15 not defined in > file libstdc++.so.6 with link time reference > llvm-config-4.0: relocation error: > /usr/lib/llvm-4.0/bin/../lib/libLLVM-4.0.so.1: symbol > _ZTINSt13__future_base12_Result_baseE, version GLIBCXX_3.4.15 not defined in > file libstdc++.so.6 with link time reference > llvm-config-4.0: relocation error: > /usr/lib/llvm-4.0/bin/../lib/libLLVM-4.0.so.1: symbol > _ZTINSt13__future_base12_Result_baseE, version GLIBCXX_3.4.15 not defined in > file libstdc++.so.6 with link time reference > llvm-config-4.0: relocation error: > /usr/lib/llvm-4.0/bin/../lib/libLLVM-4.0.so.1: symbol > _ZTINSt13__future_base12_Result_baseE, version GLIBCXX_3.4.15 not defined in > file libstdc++.so.6 with link time reference > ... > > > My first guess would be that the #727621 fix might be missing > or broken in GCC 7.
no, apparently it's an incomplete backport of the fix for PR64735. and it's missing the changes to the symbol versioning. I don't think that adding the missing bits to the gcc-6 source would make sense. The symbol is at version GLIBCXX_3.4.15 in stretch (gcc-6), and at version GLIBCXX_3.4.23 in sid (gcc-7). It should work when packages are rebuilt with gcc-7, and then we have to add the now broken packages to the libstdc++6 Breaks, this should be the way forward. To work around that now, llvm (and maybe other afected packages) could be built using gcc-7 explicitly. Do you have a list of affected packages? Or work around it by defining HAVE_EXCEPTION_PTR_SINCE_GCC46 in gcc-7 and using the GLIBCXX_3.4.15 symbols. But then we diverge from the upstream ABI, and we should change it again when making gcc-7 the default. Not ideal either way ... How long is armel supposed to live? Matthias
