Created attachment 4187 [details] diffosope output Please see the attached HTML document. This seems a relatively new problem, as not that long ago python3-dev did not contain ./usr/bin/python3.5m-config. This file contains various debug GCC flags which should not be there.
This seems to have been fixed (works for me) by https://patchwork.openembedded.org/patch/147230/ "python3-core: improve reproducibility" which seems to have been forgotten to include in master.
This patch fixed the issue: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=bed1fb22ecfe3d280670571530d6d52a02fed677