Eliminate misleading pointer from blend structure (#3548)

* Eliminate misleading pointer from blend structure

The HH pointer in the blend array was set to point to the hidden structure in the grid header and used once.  But then we destroy the grid and now the pointer is pointing to junk.  Could be confusing down the road.  So now removed and we use a single variable to get the hidden content in the only place where it is needed.

* Update gmt_init.c

Sory, also add an unrelated debug statend and fix a typo

src/gmt_init.c

@@ -14016,7 +14016,7 @@ struct GMT_CTRL *gmt_init_module (struct GMTAPI_CTRL *API, const char *lib_name,
 		}
 	}
 
-	if (options) {	/* Check if any filename argument is s remote tiled dataset */
+	if (options) {	/* Check if any filename argument is a remote tiled dataset */
 		bool first_time = true;
 		int k_data;
 		unsigned int srtm_flag;
@@ -14048,6 +14048,7 @@ struct GMT_CTRL *gmt_init_module (struct GMTAPI_CTRL *API, const char *lib_name,
 
 				if (opt_R == NULL) {	/* In this context we imply -Rd */
 					wesn[XLO] = -180.0;	wesn[XHI] = +180.0;	wesn[YLO] = -90.0;	wesn[YHI] = +90.0;
+					GMT_Report (API, GMT_MSG_DEBUG, "Modern: Assuming -Rd since %s was given and no -R specified\n", opt->arg);
 				}
 				else {
 					char codes[3] = {""};

src/grdblend.c

@@ -86,7 +86,6 @@ struct GRDBLEND_CTRL {
 
 struct GRDBLEND_INFO {	/* Structure with info about each input grid file */
 	struct GMT_GRID *G;				/* I/O structure for grid files, including grd header */
-	struct GMT_GRID_HEADER_HIDDEN *HH;
 	struct GMT_GRID_ROWBYROW *RbR;
 	int in_i0, in_i1, out_i0, out_i1;		/* Indices of outer and inner x-coordinates (in output grid coordinates) */
 	int in_j0, in_j1, out_j0, out_j1;		/* Indices of outer and inner y-coordinates (in output grid coordinates) */
@@ -200,6 +199,8 @@ GMT_LOCAL int grdblend_init_blend_job (struct GMT_CTRL *GMT, char **files, unsig
 	struct GMT_GRID_HEADER *h = *h_ptr;	/* Input header may be NULL or preset */
 	struct GMT_GRID_HIDDEN *GH = NULL;
 	struct GMT_GRID_HEADER_HIDDEN *HH = NULL;
+	struct GMT_GRID_HEADER_HIDDEN *HHG = NULL;
+
 	char *sense[2] = {"normal", "inverse"}, buffer[GMT_BUFSIZ] = {""}, res[4] = {""};
 	static char *V_level = GMT_VERBOSE_CODES;
 	char Iargs[GMT_LEN256] = {""}, Rargs[GMT_LEN256] = {""}, cmd[GMT_LEN256] = {""};
@@ -314,7 +315,6 @@ GMT_LOCAL int grdblend_init_blend_job (struct GMT_CTRL *GMT, char **files, unsig
 			GMT_Report (GMT->parent, GMT_MSG_ERROR, "Internal snafu - please report the problem on the GMT issues page\n");
 			return (-GMT_NOT_A_VALID_LOGMODE);
 		}
-		B[n].HH = gmt_get_H_hidden (B[n].G->header);
 		B[n].weight = L[n].weight;
 		if (!strcmp (L[n].region, "-"))
 			gmt_M_memcpy (B[n].wesn, B[n].G->header->wesn, 4, double);	/* Set inner = outer region */
@@ -502,8 +502,10 @@ GMT_LOCAL int grdblend_init_blend_job (struct GMT_CTRL *GMT, char **files, unsig
 		/* Allocate space for one entire row for this grid */
 
 		B[n].z = gmt_M_memory (GMT, NULL, B[n].G->header->n_columns, gmt_grdfloat);
+		HHG = gmt_get_H_hidden (B[n].G->header);
+
 		GMT_Report (GMT->parent, GMT_MSG_INFORMATION, "Blend file %s in %g/%g/%g/%g with %s weight %g [%d-%d]\n",
-			B[n].HH->name, B[n].wesn[XLO], B[n].wesn[XHI], B[n].wesn[YLO], B[n].wesn[YHI], sense[B[n].invert], B[n].weight, B[n].out_j0, B[n].out_j1);
+			HHG->name, B[n].wesn[XLO], B[n].wesn[XHI], B[n].wesn[YLO], B[n].wesn[YHI], sense[B[n].invert], B[n].weight, B[n].out_j0, B[n].out_j1);
 
 		if (!B[n].memory && GMT_Destroy_Data (GMT->parent, &B[n].G)) return (-GMT_RUNTIME_ERROR);	/* Free grid unless it is a memory grid */
 	}