$ git clone -n https://src.fedoraproject.org/rpms/tcl-snack.git /var/lib/mock/f42-build-3304144-41426/root/chroot_tmpdir/scmroot/tcl-snack
Cloning into '/var/lib/mock/f42-build-3304144-41426/root/chroot_tmpdir/scmroot/tcl-snack'...
$ git fetch origin 8c2f85a058f0d61df697fc073d5e8050268d8ce6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/tcl-snack
 * [new ref]         8c2f85a058f0d61df697fc073d5e8050268d8ce6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8c2f85a force -std=gnu17 for ugly old code, force build against tcl8/tk8