The emacs-nox package fails to build with target set to armv7l but
xdp-tools does not need it to be able to work with correct target. It is
only used to generate man pages and for that we can use build package.
checkInputs used to be added to nativeBuildInputs. Now we have
nativeCheckInputs to do that instead. Doing this treewide change allows
to keep hashes identical to before the introduction of
nativeCheckInputs.
