I'm using the generated folder structure that dh_make generates.
Everything is good as long as I mantain this structure:
./debian/
./debian/rules
./debian/<rest_of_files>
./Makefile
When I execute fakeroot debian/rules clean binary it does make clean && make && make install DESTDIR=properplace and everything works as my Makefile has those targets.
Now I wanted to move debian/rules to packaging/debian/rules but nothing works.
I try fakeroot packaging/debian/rules clean binary but that apparently looks for Makefile in ./packaging/ and not in $CWD
EDIT:
As others stated the build scripts don't like this, as a workaround I do this from the main makefile
package-debian:
ln -s packaging/debian debian
fakeroot debian/rules clean binary
rm debian
Don't do that. It's not supported. The debian directory must be under the top level.
Even if you get it to work otherwise, which I doubt, everyone will hate you because it would break every tool in the world. ;-)