$ git clone -n https://gitee.com/fundawang/libpng.git /var/lib/mock/dist-an23-build-173335-59009/root/chroot_tmpdir/scmroot/libpng
Cloning into '/var/lib/mock/dist-an23-build-173335-59009/root/chroot_tmpdir/scmroot/libpng'...
$ git reset --hard f17e1415e846f553f2c857bf7c2c17983803ec76
HEAD is now at f17e141 1.6.39