Skip dissecting opt->names in parse_config if it doesn't exist.

cgminer.c

@@ -1333,6 +1333,9 @@ static char *parse_config(json_t *config, bool fileconf)
 		/* We don't handle subtables. */
 		assert(!(opt->type & OPT_SUBTABLE));
 
+		if (!opt->names)
+			continue;
+
 		/* Pull apart the option name(s). */
 		name = strdup(opt->names);
 		for (p = strtok(name, "|"); p; p = strtok(NULL, "|")) {