#866354 is a libstdc++6 ABI change in gcc 6 -> 7 only affecting armel caused by the #727621 backport to the stretch gcc (the symbols in the backport to gcc-6 and in upstream gcc >= 7 are at different versions).
Cases where binNMUs are required are handled in #874124. Breaks for stretch -> buster upgrades will be handled in #866354. #873609 is now fixed gb llvm-toolchain-3.9_1:3.9.1-13 . armel armhf . --extra-depends "gcc-7 (>= 7.2.0-2)" #866354 gbs gb afl_2.50b-1 . armel . --extra-depends "libclang-3.9-dev (>= 1:3.9.1-13)" gb aspectc++_1:2.2+git20170823-1 . armel gb kdevelop 4:5.1.2-1 . armel . --extra-depends "libclang-3.9-dev (>= 1:3.9.1-13)" gb libc++_4.0.1-1 . armel gb llvmlite_0.19.0-2 . armel gb mesa_17.1.5-1 . armel # waiting for llvm-defaults transition (see #869602) gb libclang-perl_0.09-4 . armel . --extra-depends "llvm (>= 1:4.0)" Thanks in advance Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed