grdfill fails, probably in situation where holes extend to the edge of the grid domain

I have found that grdfill is failing, running into a segmentation fault. I am running gmt 6.4.0 on MacOS. It fails when trying to do certain operations on a grid which has lots of nans running up against the edge of the grid. It fails when using -L and -Ac but not -An. (I have not tried other options)

Command that creates failure: (the file D20191226.nc can be found here: https://drive.google.com/file/d/1rDbvuEidaeIdsuik0O7kSReNcsjzoVt2/view?usp=sharing)

gmt grdfill D20191226.nc -Ac -GD20191226_HOLESFILLED.nc -Vd

**Full error message**

gmt [DEBUG]: GMT_Create_Session: Terminal width = 122
gmt [DEBUG]: Obtained the ppid from parent: 36863
gmt [DEBUG]: Enter: gmtinit_new_GMT_ctrl
gmt [DEBUG]: GMT->session.SHAREDIR = /Users/mlees/.conda/envs/general_science/share/gmt
gmt [DEBUG]: GMT->session.HOMEDIR = /Users/mlees
gmt [DEBUG]: GMT->session.USERDIR = /Users/mlees/.gmt [created]
gmt [DEBUG]: GMT->session.CACHEDIR = /Users/mlees/.gmt/cache [created]
gmt [DEBUG]: GMT: 0. Will try to find subdir=postscriptlight stem = PSL_custom_fonts suffix=.txt
gmt [DEBUG]: GMT: 1. gmt_getsharepath trying current dir
gmt [DEBUG]: GMT: 2. gmt_getsharepath trying USERDIR /Users/mlees/.gmt
gmt [DEBUG]: GMT: 3. gmt_getsharepath trying USERDIR subdir /Users/mlees/.gmt/postscriptlight
gmt [DEBUG]: GMT: 4. gmt_getsharepath trying SHAREDIR subdir /Users/mlees/.conda/envs/general_science/share/gmt/postscriptlight
gmt [DEBUG]: GMT: 5. gmt_getsharepath trying SHAREDIR /Users/mlees/.conda/envs/general_science/share/gmt
gmt [DEBUG]: GMT: 6. gmt_getsharepath failed
gmt [DEBUG]: Map distance calculation will be Cartesian
gmt [DEBUG]: Exit: gmtinit_new_GMT_ctrl
gmt [DEBUG]: Enter: New_PSL_Ctrl
gmt [DEBUG]: Exit: New_PSL_Ctrl
gmt [DEBUG]: Enter: gmt_manage_workflow
gmt [DEBUG]: Exit : gmt_manage_workflow
gmt [DEBUG]: Enter: PSL_beginsession
gmt [DEBUG]: Exit : PSL_beginsession
gmt [DEBUG]: Enter: PSL_setdefaults
gmt [DEBUG]: Exit : PSL_setdefaults
gmt [DEBUG]: Enter: gmtlib_io_init
gmt [DEBUG]: Exit : gmtlib_io_init
gmt [DEBUG]: Enter: gmt_hash_init
gmt [DEBUG]: Exit: gmt_hash_init
gmt [DEBUG]: Enter: gmt_hash_init
gmt [DEBUG]: Exit: gmt_hash_init
gmt [DEBUG]: Enter: gmt_reload_settings
gmt [DEBUG]: The PROJ_GEODESIC set to Vincenty
gmt [DEBUG]: Look for file /Users/mlees/gmt.conf
gmt [DEBUG]: Look for file /Users/mlees/.gmt/gmt.conf
gmt [DEBUG]: Look for file /Users/mlees/.gmt/server/gmt.conf
gmt [DEBUG]: Look for file /Users/mlees/.gmt/cache/gmt.conf
gmt [DEBUG]: Could not find file gmt.conf
gmt [DEBUG]: Exit: gmt_reload_settings
gmt [DEBUG]: Enter: gmtlib_plot_C_format
gmt [DEBUG]: Exit: gmtlib_plot_C_format
gmt [DEBUG]: Enter: gmtinit_get_history
gmt [DEBUG]: Enter: gmt_hash_init
gmt [DEBUG]: Exit: gmt_hash_init
gmt [DEBUG]: Exit: gmtinit_get_history
gmt [DEBUG]: Initialize FFTW with 8 threads.
gmt [DEBUG]: GMT_Create_Session initialized GMT structure
gmt [DEBUG]: Loading core GMT shared library: libgmt.dylib
gmt [DEBUG]: Shared Library # 0 (core). Path = libgmt.dylib
gmt [DEBUG]: Loading GMT plugins from: /Users/mlees/.conda/envs/general_science/lib/gmt/plugins
gmt [DEBUG]: Shared Library # 1 (supplements). Path = /Users/mlees/.conda/envs/general_science/lib/gmt/plugins/supplements.so
gmt [DEBUG]: Revised options: D20191226.nc -Ac0.0 -GD20191226_HOLESFILLED.nc -Vd
grdfill [DEBUG]: Found readable file D20191226.nc
grdfill [DEBUG]: Replace file D20191226.nc with path D20191226.nc
grdfill [DEBUG]: Replace file D20191226.nc with D20191226.nc
grdfill [DEBUG]: Found readable file D20191226.nc
grdfill [DEBUG]: Replace file D20191226.nc with path D20191226.nc
grdfill [DEBUG]: Found readable file D20191226.nc
grdfill [DEBUG]: Replace file D20191226.nc with path D20191226.nc
grdfill [DEBUG]: Found readable file D20191226.nc
grdfill [DEBUG]: Object ID 0 : Registered Grid File D20191226.nc as an Input resource with geometry Surface [n_objects = 1]
grdfill [DEBUG]: gmtapi_begin_io: Input resource access is now enabled [container]
grdfill [DEBUG]: gmtapi_import_grid: Passed ID = 0 and mode = 1
grdfill [DEBUG]: Found readable file D20191226.nc
grdfill [DEBUG]: Calling nc_open on D20191226.nc, ncid = 65536, err = 0
grdfill [DEBUG]: Calling nc_close on ncid 65536, err = 0
grdfill [DEBUG]: Calling nc_open on D20191226.nc, ncid = 65536, err = 0
grdfill [DEBUG]: Calling nc_close on ncid 65536, err = 0
grdfill [DEBUG]: Call gmtgrdio_doctor_geo_increments on a geographic grid
grdfill [DEBUG]: Geographic input grid, longitudes span less than 360
grdfill [DEBUG]: GMT_End_IO: Input resource access is now disabled
grdfill [DEBUG]: gmtapi_begin_io: Input resource access is now enabled [container]
grdfill [DEBUG]: gmtapi_import_grid: Passed ID = 0 and mode = 2
grdfill [INFORMATION]: Reading grid from file D20191226.nc
grdfill [DEBUG]: Calling nc_open on D20191226.nc, ncid = 65536, err = 0
grdfill [DEBUG]: packed z-range: [-0.179119,0.0716667]
grdfill [DEBUG]: Calling nc_close on ncid 65536, err = 0
grdfill [DEBUG]: Geographic input grid, longitudes span less than 360
grdfill [DEBUG]: Chosen boundary condition for all edges: geographic
grdfill [INFORMATION]: gmt_grd_BC_set: Set boundary condition for all edges: natural
grdfill [INFORMATION]: gmt_grd_BC_set: Set boundary condition for left edge: natural
grdfill [INFORMATION]: gmt_grd_BC_set: Set boundary condition for right edge: natural
grdfill [INFORMATION]: gmt_grd_BC_set: Set boundary condition for bottom edge: natural
grdfill [INFORMATION]: gmt_grd_BC_set: Set boundary condition for top edge: natural
grdfill [DEBUG]: GMT_End_IO: Input resource access is now disabled
Segmentation fault: 11