$ git clone -n https://src.fedoraproject.org/rpms/libgcroots.git /var/lib/mock/f33-build-155452-43375/root/chroot_tmpdir/scmroot/libgcroots
Cloning into '/var/lib/mock/f33-build-155452-43375/root/chroot_tmpdir/scmroot/libgcroots'...
$ git reset --hard 6901121f7d27d53ac2c11a3cc15af7780b6c27e0
HEAD is now at 6901121 Fix FTBFS.