a gcc-4.4-cross-<something> source package has to build-depend on the gcc-4.4-source package. It must not duplicate the tarball inside the source package. The build-dependency on the gcc-4.4-source is needed. Wether the patches and rules files are used from the gcc-4.4-source binary package, or the gcc-4.4-cross-<something> source package is up to the gcc-4.4-cross-<something> source package.
a gcc-4.4- cross-< something> source package has to build-depend on the gcc-4.4-source package. It must not duplicate the tarball inside the source package. The build-dependency on the gcc-4.4-source is needed. Wether the patches and rules files are used from the gcc-4.4-source binary package, or the gcc-4.4- cross-< something> source package is up to the gcc-4.4- cross-< something> source package.