lib/Instructions.c by hand, which I hope I did properly. Here are my changes:

- renamed CONTOL structure members ORTHO and ORTHOZ to CITCOM_ORTHO and CITCOM_ORTHOZ
  Those were never used and conflicted with definitions in GMT gmt.h

- Added a higher frequency heat flow output option like so:

 
write_q_files=1                       # option to write heat flux to files qt.dat and qb.dat 
                                      # at intervals smaller than storage_spacing (0)


- Added the capability to read in initial temperatures from netcdf grd files, if -USE_GGRD is used. 
  Lot of options, like so:

#
# read initial temperature conditions from grd files (default values in parentheses)
#
tic_method=4                          # read initial temperature from netcdf GRD files (off)

ggrd_tinit_scale_with_prem=off        # scale the temperature with PREM densities (off)

ggrd_tinit_scale=1.0                  # scaling factor to apply to read in scalars f (1.0)

ggrd_tinit_offset=-0.5                 # offset, T = f * scale + offset + tm   (0.0)
                                       # where tm is the mean between top and bottom TBC values
                                       # if the bottom is flux, will use 1 for bottom TBC value

ggrd_tinit_gfile="../../data/tomography/s20a_smean_new_age/t" # prefix of grd files, will 
                                                              # try to read t.1.grd, t.2.grd ... t.n.grd
                                                              # where n is the number of layers in the depth file
ggrd_tinit_dfile="../../data/tomography/s20a_smean_new_age/tdepth.dat" # file with layer depths in km from bottom up

ggrd_tinit_prem_file="../../progs/src/hc-svn/prem/prem.dat"  # PREM data file
ggrd_tinit_override_tbc=on            # override temperature boundary conditions (off)