$ git clone -n https://gitee.com/fundawang/libcxx.git /var/lib/mock/dist-an23-build-252489-63489/root/chroot_tmpdir/scmroot/libcxx
Cloning into '/var/lib/mock/dist-an23-build-252489-63489/root/chroot_tmpdir/scmroot/libcxx'...
$ git reset --hard 19b4c98729f2c2a79e8eac982bbb5846ba249ab0
HEAD is now at 19b4c98 16.0.1