The rules file use the make variable $(_).
According to Policy 4.9, 'invoking either of
make -f debian/rules
<args...>' must result in identical behavior'.
One way to inadvertently violate this policy is to use the $_ variable.
If the rules file uses $(dir $(_)) to discover the directory containing the source package (presumably in order to implement the get-orig-source target), please replace it by $(dir $(firstword $(MAKEFILE_LIST))).
For more information please consult:
The tag is present in Lintian version
That is the most recent version we know about.
We use semantic versions.
The patch number is a commit step indicator relative to the
release tag in our Git
You can find the detection logic for this version at commit ffc17eb. For merge requests, please use the latest version in the Lintian check debian/rules.