manual debian/rules build fails

[TJ]

With the current package in 21.04 dev (4.4-1) manually downloaded via dget an initial build fails due to artifacts (symlinks to system-installed fonts) of the build process. Comparing to the builder logs I see that a 'clean' is required to remove them. I've never hit this with other package's builds and I've done many so wondering if this is a bug with this package.

$ dget -x http://archive.ubuntu.com/ubuntu/pool/universe/g/gnucash-docs/gnucash-docs_4.4-1.dsc
...
$ cd gnucash-docs-4.4
$ debian/rules build
...
configure: WARNING: unrecognized options: --disable-maintainer-mode, --disable-dependency-tracking
   debian/rules override_dh_auto_build
make[1]: Entering directory '/media/ubuntu/SourceCode/gnucash/gnucash-docs-4.4'
mkdir -pv fonts/truetype
ln -sv /usr/share/fonts/truetype/horai-umefont/ume-tgo4.ttf fonts/truetype/ # fonts-horai-umefont
ln: failed to create symbolic link 'fonts/truetype/ume-tgo4.ttf': File exists
make[1]: *** [debian/rules:31: override_dh_auto_build] Error 1
make[1]: Leaving directory '/media/ubuntu/SourceCode/gnucash/gnucash-docs-4.4'
make: *** [debian/rules:13: build] Error 2