$ git clone -n https://gitee.com/opencloudos-stream/libcxx.git /var/lib/mock/dist-oc9-epol-build-66159-16665/root/chroot_tmpdir/scmroot/libcxx
Cloning into '/var/lib/mock/dist-oc9-epol-build-66159-16665/root/chroot_tmpdir/scmroot/libcxx'...
$ git fetch origin master:KOJI_FETCH_HEAD
From https://gitee.com/opencloudos-stream/libcxx
 * [new branch]      master     -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 390f6b4 !2 【软件升级】 [libcxx] 可升级至 [17.0.6] Merge pull request !2 from luochenglcs/master