$ git clone -n https://src.fedoraproject.org/rpms/ghc-rfc5051.git /var/lib/mock/f31-build-101037-33344/root/chroot_tmpdir/scmroot/ghc-rfc5051
Cloning into '/var/lib/mock/f31-build-101037-33344/root/chroot_tmpdir/scmroot/ghc-rfc5051'...
$ git reset --hard 9c09091669fc9d1130b14520148b67eaa85781f8
HEAD is now at 9c09091 BR prof for lib and static for executable