Niels warned in this bug report that debhelper is going to require all
dh_* commands to be run from the toplevel directory at some point. He
reverted dh_testroot's failure to just a warning when debian/control
can't be read; but it will become a hard failure at some point, which
cannot be accounted for through a compatibility level (one would need to
read debian/compat anyway…):

    Bug#879478: debhelper: dh_testroot regression: relies on debian/control

We seem to be only calling dh_testroot twice from build/Makefile, and
no other dh_* commands outside debian/rules.


KiBi.