Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. NetworkManager-openvpn 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/NetworkManager-openvpn/NetworkManager-openvpn-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
I think autoreconf -i is the best thing to do for now. The only reason it ships with autoconf < 2.69 config.guess/config.sub is because I made the dist tarballs with an older autoconf, and NetworkManager-openvpn hasn't been updated for a while.
Fixed in NetworkManager-openvpn-0.9.8.2-4.fc19.