$ git clone -n https://github.com/xcp-ng-rpms/gcc-xs.git /var/lib/mock/v7.99-base-529-247/root/chroot_tmpdir/scmroot/gcc-xs
Cloning into '/var/lib/mock/v7.99-base-529-247/root/chroot_tmpdir/scmroot/gcc-xs'...
$ git reset --hard e71d0424a6d09cc510210e043dd49b0f1b853a61
Downloading SOURCES/gcc-xs-7.3.0.tar.gz (98 MB)
HEAD is now at e71d042 Add BuildRequires: gcc