If called from external with -Vi or lower, print command string (#4131)

* If called from external with -Vi or lower, print command string

For simpler debugging from external calls, we echo out the module call string when -Vi is used.

* Update gmt_api.c

* Update gmt_api.c

* Change to -Vd instead

* Update src/gmt_api.c

Co-authored-by: Dongdong Tian <[email protected]>

Co-authored-by: Dongdong Tian <[email protected]>

Author: PaulWessel

src/gmt_api.c

@@ -11034,6 +11034,12 @@ int GMT_Call_Module (void *V_API, const char *module, int mode, void *args) {
 	else {	/* Call the function and pass back its return value */
 		gmt_manage_workflow (API, GMT_USE_WORKFLOW, NULL);		/* First detect and set modern mode if modern mode session dir is found */
 		gmtapi_check_for_modern_oneliner (API, module, mode, args);	/* If a modern mode one-liner we must switch run--mode here */
+		if (API->external && gmt_M_is_verbose (API->GMT, GMT_MSG_DEBUG)) {
+			/* For externals only, print the equivalent command-line string under -Vd */
+			char *text = (mode == GMT_MODULE_OPT) ? GMT_Create_Cmd (API, args) : args;
+			GMT_Report (API, GMT_MSG_DEBUG, "GMT_Call_Command string: %s %s\n", module, text);
+			if (mode == GMT_MODULE_OPT) GMT_Destroy_Cmd (API, &text);
+		}
 		status = (*p_func) (V_API, mode, args);				/* Call the module in peace */
 	}
 	return (status);