$ git clone -n https://src.fedoraproject.org/rpms/libgcroots.git /var/lib/mock/f29-build-7197-1771/root/thebuilddir/tmp/scmroot/libgcroots
Cloning into '/var/lib/mock/f29-build-7197-1771/root/thebuilddir/tmp/scmroot/libgcroots'...
$ git reset --hard 13d2319f43f417536cc532c4de87f98f6ff0d162
HEAD is now at 13d2319 Add BR: gcc-c++