tohost is not required in hifive1 env

bare-metal-bsp/libwrap/sys/_exit.c

@@ -16,7 +16,9 @@ void __wrap__exit(int code)
   write(STDERR_FILENO, message, sizeof(message) - 1);
   write_hex(STDERR_FILENO, code);
   write(STDERR_FILENO, "\n", 1);
+#ifdef USE_TOHOST
   tohost = code+1;
+#endif
   write(STDERR_FILENO, "\x04", 1);
   for (;;);
 }