Silly bug in gr_fmdet_cf.cc

Just came across a typo in gr_fmdet_cf.cc (compare to previous version
to
see the correct code). Line 87 currently reads:

Sdot = d_scl * (-S0+d_8S1-d_8S1+S4);

Note that the middle two terms are identical and therefore don’t do
anything. The correct code should read:

Sdot = d_scl * (-S0+d_8S1-d_8S3+S4);

I am no longer actively working with GR and don’t recall how to submit a
patch request, plus my version is very old. I’d appreciate somebody
putting the patch in for me.

Thanks,