rework structure

hifive1-vp/hello/bsp/libwrap/sys/_exit.c

@@ -0,0 +1,16 @@
+/* See LICENSE of license details. */
+
+#include <unistd.h>
+#include "platform.h"
+
+void __wrap__exit(int code)
+{
+//volatile uint32_t* leds = (uint32_t*) (GPIO_BASE_ADDR + GPIO_OUT_OFFSET);
+  const char message[] = "\nProgam has exited with code:";
+//*leds = (~(code));
+
+  write(STDERR_FILENO, message, sizeof(message) - 1);
+  write(STDERR_FILENO, "\n", 1);
+
+  for (;;);
+}