Support for the ARM 64 bit CPU architecture (aarch64) was introduced in autoconf 2.69. kBuild 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/kBuild/kBuild-aarch64.patch which updates config.guess and config.sub to recognize aarch64.
From what I see in build.log mkdir -p /builddir/build/BUILD/kBuild/out/linux.amd64/release/bootstrap/sed autoreconf: Entering directory `.' autoreconf: running: autopoint --force (...) autoreconf: running: /usr/bin/autoconf --force autoreconf: running: /usr/bin/autoheader --force autoreconf: running: automake --add-missing --copy --force-missing also looking to kBuild/src/sed/config/ ll /var/lib/mock/fedora-rawhide-x86_64/root/builddir/build/BUILD/kBuild/src/sed/config/ -tr config.guess was generated by build , so I assume this bug is fixed at least in current release , I'm closing bug , feel free to reopen it . and please check it out if kBuild support aarch64 !