Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. pg_top 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/pg_top/pg_top-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
Fixed in rawhide. http://pkgs.fedoraproject.org/cgit/pg_top.git/commit/?id=9e843589cbb45830b1032d2999d36373d3d62d0b http://koji.fedoraproject.org/koji/taskinfo?taskID=6869339