lwatch riscv fix

I am trying to fix the package lwatch_0.6.2-1 so that it works on riscv. I was able to reproduce the error found in the most recent build log for lwatch on riscv. I found the issue in the dpkg-buildpackage process where it calls an incorrect setting string for the configure script. The debian/rules file currently calls: ./configure --host=$(DEB_HOST_GNU_TYPE) --build=$(DEB_BUILD_GNU_TYPE). These environment variables come from dpkg-architecture which gives 'riscv64-linux-gnu'. The package builds and compiles properly when running ./configure --host=riscv64-unknown-linux-gnu --build=riscv64-unknown-linux-gnu. I have seen the 'unknown' part in these build/host strings before and am not sure what the difference is.

So it appears either dpkg-architecture is giving an incorrect string for this build, or the debian/rules file needs to be modified for lwatch specifically to allow it to work for riscv. I can build the package by adding an if check for riscv and hard-coding the riscv64-unknown-linux-gnu strings in the configure part, but this does not feel like best practice. Is there a way to change the environment variable for riscv? Or is there another solution for making the changes in debian/rules?