$ git clone -n https://src.fedoraproject.org/rpms/perl-Cairo.git /var/lib/mock/f40-build-778106-129765/root/chroot_tmpdir/scmroot/perl-Cairo
Cloning into '/var/lib/mock/f40-build-778106-129765/root/chroot_tmpdir/scmroot/perl-Cairo'...
$ git fetch origin bbbe0274072a8ef45739672a3777f69876c86fee:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Cairo
 * [new ref]         bbbe0274072a8ef45739672a3777f69876c86fee -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bbbe027 use proper STRLEN type, fixes FTBFS on i686