from the dh manpage:
Finally, remember that you are not limited to using override targets in
the rules file when using dh. You can also explicitly define any of the
regular rules file targets when it makes sense to do so. A common
reason to do this is if your package needs different build-arch and
build-indep targets. For example, a package with a long document build
process can put it in build-indep to avoid build daemons redundantly
building the documentation.
#!/usr/bin/make -f
%:
dh $@
build: build-arch build-indep ;
build-indep:
$(MAKE) docs
build-arch:
$(MAKE) bins