Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. virt-dmesg 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 configure. 3. Apply the patch at http://ausil.fedorapeople.org/aarch64/virt-dmesg/virt-dmesg-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
Fixed in virt-dmesg-0.3.0-9.fc20