While I am at implementing T167, and before I update the generic makefile in the packages, I could add a few more changes if required.
By the way, you can now drop snippets into a to-be-created-if-needed ./make-helper-overrides.d/ folder. When they are executable, they will be sourced in lexical order. Alternatively use ./make-helper-overrides.bsh. Useful to overwrite functions by make-helper.bsh.
Also added generic _hook_pre and _hook_post mechanism. Before calling any make helper function, function function-name_hook_pre would be called and function-name_hook_post after running the the make helper function.
For example. Let's take function make_deb-pkg. You could define a make_deb-pkg_hook_pre or make_deb-pkg_hook_post using overrides.