I may have seen something similar with ubuntu core today on raspberry pi3 (using the classic snap, which is at 16.04.2) fakeroot is 1.20.2-1ubuntu1.
Here's what I saw while packaging a version of graphicsmagick (about three hours into a script that dh_builddeb dpkg-deb: building package 'blort-graphicsmagick' in '../blort-graphicsmagick_XX.YY_armhf.deb'. semop(1): encountered an error: Invalid argument dpkg-deb: error: subprocess tar -cf returned error exit status 1 dh_builddeb: dpkg-deb --build debian/blort-graphicsmagick .. returned exit code 2 semop(1): encountered an error: Identifier removed dh_builddeb: dpkg-deb --build debian/blort-graphicsmagick-dbg .. returned exit code 1 debian/rules:4: recipe for target 'binary' failed make: *** [binary] Error 1 /usr/bin/fakeroot: line 1: kill: (8907) - No such process dpkg-buildpackage: error: fakeroot debian/rules binary gave error exit status 2 debuild: fatal error at line 1376: dpkg-buildpackage -rfakeroot -D -us -uc -b failed program finished with exit code 29 I have not tried your patches or turning on debugging output yet. I'm rerunning debuild now, but it's bedtime, I'll have to check in the morning (raspberry pi rather dreadfully slow).
