Support for the ARM 64 bit CPU architecture (aarch64) was introduced in
autoconf 2.69. viewnior appears to use an earlier version of
autoconf, preventing its being built. This can be fixed in of three ways (In order of preference):
1. Work with upstream to migrate the package to autoconf 2.69.
2. Rerun autoconf or autoreconf in %prep or %build prior to running
3. Apply the patch at http://ausil.fedorapeople.org/aarch64/viewnior/viewnior-aarch64.patch
which updates config.guess and config.sub to recognize aarch64.
viewnior-1.3-4.fc19 has been submitted as an update for Fedora 19.
viewnior-1.3-4.fc19 has been pushed to the Fedora 19 stable repository. If problems still persist, please make note of it in this bug report.