Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. cproto 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/cproto/cproto-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
Fixed in rawhide. http://pkgs.fedoraproject.org/cgit/cproto.git/commit/?id=76aea787798806d1eb8a8763d0bca9730a581fdf http://koji.fedoraproject.org/koji/taskinfo?taskID=6860197