Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. irsim 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/irsim/irsim-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
irsim builds fine for ARM on F19, and F20. http://arm.koji.fedoraproject.org/koji/taskinfo?taskID=1742474 http://arm.koji.fedoraproject.org/koji/taskinfo?taskID=1742474
A patch to redhat-rpm-config has effectively resolved this issue for aarch64. We have built the package successfully in bootstrap.